FSE

Furry search engine

formerly SoFurry search engine

Dynamics

Part four of four

---

Written by Arian Mabe (Amethyst Mare)

Commissioned by Cougar

She wasn't pushing him but was leading him in to offer him something more, allowing him the room to speak. Even though his tail lashed back and forth, the strained cougar tried to hold it back and down, grunting thickly in the back of his throat.

"Tell me, Mark."

Oh, that command... That was what changed it for him. That had him straightening his back ever so slightly, his breath hitching and catching.

It was everything he needed. For, if Mercy was in control, that meant that everything was okay. She'd never do anything bad to him and he could trust her, for it was that very trust that resided at the core of everything.

It was something that he had not paid due attention to before, though he knew how important it was, even as he focused on how good her small chest felt against his back, the warmth of her seeping through.

Oh...

_ _

Was it... He struggled mentally, though the reassuring squeeze of Mercy's arms around him let him know that everything was okay. He didn't have to worry, even if his heart was pounding, even if his hackles were trying to rise, the fur all over his body prickling up and trying to stand on end. Even Mark's tail was a little fluffier than it had been before.

"I..."

"Tell me, Mark."

"I want..." Oh, it was so hard for him to get the words out. "I want... It's...exciting to think...of it...of you..."

He couldn't get the words out, though he hoped that it would be enough. Or did he not want it to be enough? Something was changing, something was shifting, something that they could never go back from. It felt like it was spiralling out of his control and into Mercy's all at once, though he was glad too, in a way, that it was not the case that nobody was in control.

Especially for the cougar, he needed somebody to be in control.

"That's okay, brother," she said, her lips very close to his ear. "You're okay... I want this too."

They didn't say it explicitly, though he caught himself letting out a breath, eyes half-closed even though his body had become electrified. He thrummed with desire, his hard-on pulsating softly, though it did not yet feel as if it was fully hard quite yet. That wasn't the most important thing, however, even as it was an outward demonstration of his enjoyment of the moment, how it throbbed and pulsed lightly, a smear of pre-cum cooling right at the tip.

For a moment, they were quiet, sexual tension charged and crackling in the air while the din of rain on the roof of the van filled the space around them. Yet it was not enough to cover the desire building, strung out between them like a cord that was just waiting to be snapped - yet the moment in which it snapped would leave them with one another, facing the lust in the room that had been swelling without either of them acknowledging what lay there.

Mercy growled faintly and a shock ran down his spine, straightening swiftly against her.

"Okay," she said quietly, though her tail swept wantonly back and forth through the bed, stirring up the sheets, betraying her excitement still. "Then... Your safe word will only be safe word. If you want anything to stop, at any point, you will use the safe word. What is your safe word?"

He blinked, not sure what she wanted for a moment. Hadn't she already said it?

"My safe word...is safe word?"

Why did that make him tingle all over?

"Good boy," she said, her voice dropping into the hint of a purr. "Now... When do you use your safe word?"

Ah, now he understood. She was making sure that there was a clear stop for both of them, once again looking after him and proving herself to be someone that he could trust. After everything that he had gone through before, he had to run through that in his mind, making it clear to himself while Mercy did exactly the same.

"I use my safe word whenever or if things are going too far, if I want to stop at any point."

"Or even if you want to slow down or say something," she stressed. "Anything at all. And now..."

She moved over him, kicking the sheets aside, for they would not be needed as passion was allowed to roar between them. He caught his breath, but she was on top of him in but a moment as her paws slid over his shoulders, lightly pinning him in place. Even though Mark would have been able to wriggle free from her at that point...

Oh. No, no, he could not squirm free of her. His sister closed her powerfully muscled thighs around him and squeezed, letting him feel the inherent strength of her body, what she honed every single day of her life, her fingers curling around his shoulders.

"Ooof..."

He let out a low, needy groan, though his heart was pounding so heavily that he didn't know whether he was listening to his heart beating or the drum of rain on the roof. He didn't even know if it mattered anymore, not as things changed, the shift of desire between them not something that could ever again be put back as it was.

They had to see it through, especially as she pinned him in place, casually controlling him physically and putting him in the position that she wanted him without seeming to take a second thought about it.

"I'd tell you to strip but it's so much more fun to do this myself!"

Her words came with a twist of relish curling through them and Mark barely had a moment in which to gasp, though there was a moan wound through the depths of his cry too, as if his soul had to set it free.

"I'll take the lead."

He didn't say anything, wanting to see, though he felt as excited as he felt safe as she ripped his shirt off and over his head, though it felt as if he had not put it on all that long ago. Mark whimpered as he flicked his tail, wanting to be soft and amenable for her, even if the cougar never had to consider the hiding of his arousal anymore. No, his hard-on stood up hard and proud through his underwear, impossible to miss with the spot of dampness where the head of the shaft was.

"Ohhh..."

"There's a good brother, hm... You like this."

Mercy smirked and he caught the glint of her eyes in the low light. He loved how she stated things as facts, like there could be no question about it.

Mercy stripped his underwear off too, though she was rougher about it. She yanked them down quickly, which had the effect of making it so that his cock didn't catch in the cloth, for which he was grateful. It was almost painfully hard, springing up with a throb of desire, though Mercy did not touch him - not just yet.

He'd never done "it" like that before but...it was different. For she was so much stronger than his ex-girlfriend and they would never be the same, even if Mercy came with a dominant, powerful brand of domination that Mark had never before even thought could exist. All as she pinned him forcibly with a hand on his chest, pressing her weight down into him until he whined and gasped.

She knew exactly where her own limits lay, bearing down on his chest enough to remind him that his ability to breathe could be compromised. Why, he could even feel the bruises forming even then, though Mark was sure that there would be no lasting damage either, but he could use his safe word if he was ever worried about anything.

"Unff..."

"You're going to be so good for me, brother," she purred, grinning widely, her purr almost disrupted by how big her smile was. "I can't wait to feel you..."

He didn't know just what she meant or how far she was going to go with him, though Mercy well enough led the way with her hand around his cock.

"Ohhhhh, fuuuuck!"

She smirked but he didn't catch what she said, not as need roiled within him. He had not known that something that powerful could twist in the pit of his stomach, although it was very much not desire. He twisted and tried to push back against her paw on his chest but it was the weight of her that kept him there, once again letting him know how small and insignificant he was in comparison to her.

Mercy could really do anything to him and yet...she wasn't going to. And his cock was so hard, so very hard, all as she languidly stroked him, feeling out his body, exploring him. She was as firm as she needed to be, squeezing his cock, her fingers easily going around him, though he was a comfortable size.

Yet she slumped over him, her arm across his throat as the feline struggled for air. She did not bear down too much but the exact right amount for him to feel the restriction, able to claw at her, to fight back, to do something - all while she kept him right in place, exactly where she wanted him to be.

"Oooofff... Nnnggghhh..."

He groaned deeply, though his attention was purely focused on his cock, how it felt throbbing in her paw, his head spinning and spinning. Passion was mounting and Mark feared that he was going to blow right there and then, even if that didn't seem as if it was going to be anything of a problem, not anymore. It was not as if she was going to do anything bad to him or say anything bad to him, for his orgasm was for her, however Mercy wanted to take it from him.

Her arm across his throat though, putting pressure on the side of his neck, bore down, making him gulp, his chest tightening, the urge to breathe leaping forth. And she knew the effect she had on him too.

His mind didn't know where to go, jumping between his cock and his throat, how every breath of air felt as if it was hard-won, needing it more and more, even though he had just enough air to keep himself going. His shaft ached as she pumped her paw over it, though Mark could not have said what was going on in the cougar's mind, no, not at all, even if it did not matter either. As hard as she was being with him too, his cock seemed to throb even more, his throat sore, the pressure there simply exquisite.

Yet the feel of her arm across his throat, cutting off and restricting, even if only partly, his ability to breathe came with an intoxicatingly dangerous edge to it too, an edge that had his chest rising and falling sharply, making him wonder if he was okay there, if he was in the right place. He could have clawed enough air into his lungs to speak if he'd needed to but...he didn't need to use his safe word. Not with her thumb smearing tenaciously over the head of his cock, pulling a bead of pre-cum down to teasingly lubricate his length, her paw working him over, gripping him even as her teeth danced in an open-mouthed grin.

"You're so hard for me already, brother," she said, seeming to take a thrill from calling him her brother, even then. "Damn... Since you turned up here... I've only wanted to drag you back here and get you eating me out, riding you..."

"Unnff..."

He squirmed and blushed hotly, heat crawling down his neck as if it was determined, one way or the other, to make itself known. Mercy felt it that time, his body aching for her, rolling up, losing control. He didn't need to concern himself, not even as pre-cum drooled down his cock and he realised that he was grunting and thrusting, that she was having to increase the pressure on his neck just to keep him in place.

Yet, of course, Mercy had to turn the tables on him, right at the point of orgasm.

"Come here!"

Her growl ripped through him and, suddenly, he was not on his back on the bed anymore. He was tangled - tangled with Mercy! And the bigger, more powerful cougar was wrestling him, grabbing his arms, pinning them back behind his head while she caught his legs between hers. Instinctively, he thrashed, struggling back against her, though that was only because his body thought that something was wrong. It took him a moment for his mind to catch up with what was going on, bucking and arching, even though the hardness of his cock still begged for something that he should have been able to give himself.

She handled him as if he was just something to be shoved into position, her elbow in his stomach, wrapping around him as she loomed over him. The bed may have been soft under him but everything about Mercy was hard, even down to the predatory lash of her tail, back and forth back and forth.

Something in Mark lurched and he wanted to see what would happen if he pushed back, if he tried to get her to use her strength against him even more. He forced the issue, bucking his hips, growling, though the light in his eyes suddenly dared her to do it, to put him in his place.

"Brother, you are testing my patience..."

He shuddered bodily. That was all fine, within the limits, all as she grabbed his throat. But he bucked back harder against her, the cat's lips parted, wanting to feel more, to see what mercy was truly capable of.

"Unff... Brother!"

She snarled and his heart turned over, passion rising. Her fingers tightened around his throat, holding him fast, using her strength against him rather than her weight as need surged. Fuck, how could it be so hot that she was grabbing his throat, holding him down, forcing him to submit? Yet that was what he had never truly known that he had wanted. Sure, Mark could willingly submit, but where would the true pleasure be in that?

No, he needed her above him, her muscles bulging, her tail lashing, looking so predatory, so devastatingly beautiful that he would have honestly dropped to his knees and served her right then and there. He heaved and tried to kick her off but she locked her legs around his as her grip on his throat tightened, forcing him to wheeze, tears pricking in the corners of his eyes from the pressure.

It should have been terrifying and, surely, her strength thrilled him in a scary way. Yet the hardness of his cock betrayed him and he leaned heavily into him, her grip strength measured only to the point that she would not harm him.

He would be fortunate the chest day, his chest heaving for breath that would not come, that she knew how to hold herself back. She could have really hurt him, if she had wanted to, though that would never have crossed Mercy's mind. She wanted to claim him, to use him, to dominate him - but that, of course, meant that there would never again be any lasting damage made to him.

In the interim, however...

He fought and gasped and yet...it was glorious to submit to her paw around his throat. To know that she was strong enough to handle him that roughly, even though it should very much have been something that scared him. He could be scared and he could be aroused, both at the same time. That was definitely new to him, but all in a way that left the cougar wanting more, hungering for more.

Only when he went slack, submitting completely and utterly to him, did she relinquish her hold on his throat, where she had been putting pressure on his windpipe, allowing him to drag in full, deep gulps of sweet, clean air. He needed it, yes, all so very badly, yet he needed Mercy more, all in a way that he could not have envisioned craving before he had reconnected with Mercy that weekend.

Things were different, very different, though she nipped sharply at his throat. His paws were up above his head and there was a weight on his wrists, pinned there, though he was giving in to it. He needed her, needed that control even as her lips, suddenly, came roughly down on his.

He'd never had a kiss like that before, one that felt like it was sucking the life out of him, making him dizzy with sin. Oh, Mark knew that she was his sister and he should not have felt like that, but he still kissed her back just as deeply, just as passionately, heaving and grunting, her tongue dominating his mouth. It jabbed into his mouth forcibly and yet the force of her lips on his bruised them, her teeth grazing his lips.

If only he knew just how rough Mercy was willing to go with him... Maybe he would have crossed that line with them sooner, though Mark could rest assured that he had his safe word, if ever needed. That gave him a kind of security that he had never felt before, even as his cock throbbed and Mercy rolled her body sensually down against his, letting him feel the brush of her fur along the hot length of his cock, how she moaned and how he panted heavily into her mouth.

Yet her lips broke from his harshly, not paying attention to where her teeth were going. She growled and it took him a moment to realise what was happening as she bit into his neck. Yet it did not last long enough for him, too fleeting, almost like a love bite rather than the sinking, deepening crunch into his flesh that he had not realised that he had ached for. If she could wrestle and pin him into submission with her superior strength, by far so much greater than him...that meant that he could lean into his fantasies.

The fantasies that had darkened the seductive reaches of the back of his mind. He had not delved deeply, but he needed more.

But Mercy did not sink her teeth into him again, instead pushing over him, keeping his arms roughly pinned up above his head and out of the way, ignoring how his tail flicked back and forth. She spared only a moment to rip her underwear off, for it was not as if she had put all that much on either, lifting her arms to drag her T-shirt off too with such force that the seam split on one side.

He was gifted with her glorious outline, the light from outside the van in the late afternoon and early evening still illuminating the edge of her, though it was still a grey light with all the rain outside. But her thighs closed around his head as she loomed over him, grinding the sweet heat of her sex up to his muzzle.

"Lick."

She would have forced his head in so that he was forced to, though Mark was more than willing. It was too easy for him to sink into it, to feel everything, even knowing that she was his sister. He couldn't even move his head from one side to the other with the force that she put around his head, muscles bunching and contracting.

Mark didn't need to move, not as he ate her out. And, yes, it needed to be a crude term that time, for she was his sister.

"Mmm... Deeper, brother!"

The order was snapped and, still, Mark found himself leaning into that for security. He had all the physical security that he needed, even though it was hard to breathe. Why was it hard to breathe? He couldn't see, not then, that Mercy had rolled her weight back a little more so that she rested on his upper chest and collarbone, her tail sweeping across his stomach, even brushing his dick. And yet he didn't need any help at all to remain hard, no, not with the tartness of her pussy on his tongue, his lightly raspy, feline tongue driving up inside her.

Her folds parted beautifully around his tongue and Mark knew that his only will, right there and then, was to serve her, to please her. There was nothing more at all that needed to clod his mind or worry him in the slightest, though she shifted her weight so that her legs came down around his arms. Mercy so very easily pinned his arms to his sides so that he could not even use them, being squeezed from either side, gasping and heaving.

Yet the light air deprivation drove him on, forcing him to fight and claw mentally to please her, to need her, to show her that he was there for her - submissively, of course. He would never have imagined that eating out his sister could be so intoxicatingly hot, not like that, but he lost himself in it, in the tight push of her thighs, closing around his head like a vice.

And yet Mercy did not hold him so tightly that he could not please her, hissing out her pleasure as her tail lashed and lashed. He dipped his tongue even more deeply inside her, plundering her pussy as she had swept her tongue around his mouth, yet they were both very different things. One was in submissive bliss and the other was in dominant glee, though they went hand in hand.

"Mmmm..."

He purred into her pussy, slipping away, a deeper state of submission washing over him. He didn't need to fight back anymore, didn't need to push any boundaries, not as he languished there, letting the minutes roll on as he took his cues from the tiniest hints and shifts in Mercy's body.

How her breath hitched when his tongue swept over her clit.

The way in which her hips shifted forward ever so slightly when he trailed around the entrance to her sex.

How she yowled when he rammed his tongue in deep, as if he was trying to thrust, as if he thought that he was, in that moment, capable of taking her.

Yet no one could claim Mercy.

She snarled and rolled her hips against his muzzle, needing more, grunting thickly in the back of her throat. His head swirled with passion and he tried to chase the grind of her pussy with his lips and tongue, wanting her, wanting her clit. That was where all the most sensitive nerve endings, as was the case for so many, were centred for her, and he lashed her clit fervently with his tongue, trusting Mercy to be able to take the overload of pleasure.

And yet he could not ignore his own either, even with the weight on his chest, the lack of air reaching his lungs making him sinfully dizzy. He wasn't able to get enough air into his lungs, at that moment, but that was okay, because Mercy would never push him that far, even if the sense of restriction and fluttering tightness in his chest made his cock even harder. He heaved and grunted, his throat tight with emotion, needing something, craving something, even though he hardly even knew how to put it into words.

With her essence, juices trickling from her pussy and soaking the fur of his muzzle, he gasped. Tickles of warm breath wisped over her sex and Mercy looked down at him, keeping an eye on her charge, her brother, at all times.

He groaned, forcing the words out, eyes half-lidded, pupils darting back and forth, though the clamp of her thighs around him didn't allow him to look up.

"Oof... Please... Mercy, please...mark..."

She paused, ears twitching faintly as she listened to him, though his tongue was only a hair's breadth from her pussy still. He wanted to see her orgasm on his muzzle, even then, but he wanted her to claim him, to do what she had started with that little, bristling bite on his neck in the first instance.

"Yes, brother?"

Oh, her purr, it was so seductive, rolling over and through him as he panted and heaved. So tight... So held... So locked down...

He needed it. But he needed to use his words to tell her what he knew that he wanted too.

"Bite..." He blushed hard, cheeks burning. "Bite me... Please... Mark me... You can be...rougher...with me..."

Her eyes seemed to shine with inherent power.

"Good, brother," she praised him, though the pinch of her short claw-like nails biting into his wrists, where she pinned them over his head against the mattress, didn't sound as soft as her words were. "Get me off first."

That was something that he could do and he plunged his tongue back into her sex, dragging it back, over her clit, swirling it around. The motions were one thing, almost mechanic in nature - but it was the passion and the desire behind pleasing her that really did it for Mercy. The cougar arched her back and panted heavily, rasping out curses and cruder words from a filthy mouth.

And Mark did not care. He was right where he needed to be, eating her out, her juices soaking more and more into his muzzle. It may not have been the mark that he had wanted, not quite yet, but it was a mark of a kind, her arousal sinking into his fur in such a way that the scent of him would remain on him for days if he did not use special shampoos to remove it from his fur. Later, when Mercy had claimed him fully as hers, she would order him, of course, not to do so.

Yet he revelled in her groan as she climaxed, how her yowl ripped itself from her throat as if the cougar was becoming a wild beast, humping and bucking, grunting and heaving, losing herself in passion while he became but a toy for her. A well-loved toy, yes, but one that would still be very well-used, for her needs were ones that came first. He tongued her clit as much as he could, sucking it lustfully between his lips so that he could even more fervently lash it with his tongue, paying her and her body every bit of attention that she needed, his head faint.

He wheezed for breath, pain blossoming across his chest when she pulled back and away from him. She had to realise her own strength, when she bore down on him just like that, though he did not mind it, even though it was exhilarating to not be able to breathe properly, to know that she could control that, a bodily function of taking in oxygen and expelling carbon dioxide, something that would have been automatic if not for her thighs squeezing his shoulders and upper arms.

Mark grunted - but Mercy was far from done with him, of course. Nothing was stopping her from taking what she wanted from him, not when her dear brother was so willing and submissive before her, and she flipped him. Well, to the extent that there was space to do so in the span of the van, which was still quite tight and cosy for how rough she wanted to be with him.

"Oof!"

He grunted as he was flipped onto his front, heart pounding, driving in his chest. That was hot, so hot, and she pinned him by sitting on his back, wrenching an arm behind his back. His cock was trapped down between the bed and his body, aching fiercely, and there was nothing that he could do about it, not even as both his heart and his arousal surged. He licked his lips, the taste of her still thick in his muzzle, yet he couldn't move, not even as her teeth grazed his shoulder.

Her bite...

_ _

He gasped, a sharp pinch of teeth digging into his shoulder. She sank her teeth in and he exulted in it, nearly creaming himself right there and then, heaving and huffing and panting, though the blistering rise of pain came with a heated rush of pleasure too. And no words needed to be said either, not as she claimed him, as she finally marked him as hers, holding his left arm wrenched back behind his back with enough force that her fingers left bruises under his fur.

It was a good thing that fur could hide marks like that rather a lot more than bare skin, as was the case for some anthros without fur, or even reptiles that might have been prone to losing scales or the like under such rough play. Blood trickled faintly between her teeth yet his moans drove her on, biting him again, bruising his flesh too even as her teeth cut into flesh past the frail barrier of his fur.

"Unnngghhhh... Mercy..."

He gave in to her, shuddering and gasping, yet his hard-on was so fervent that he nearly climaxed. Yet he could not, because he was there for Mercy, for his sister, for everything that she wanted to do to him. Yet he could never have anticipated the response that his body gave when she sank her teeth into the scruff at the back of his neck.

It was a part of his body that would only have been useful, to his species, when he was very young, a sort of leftover from how his kind of cougar had been before evolving to walk on two legs. Still, he went limp.

Limp. Just like that.

He grunted, panting heavily, his eyes wide and a little glassy. More of his pre-cum leaked into the bed, though he didn't feel as if he could do anything at all, nothing more than to lie there, even as a sense of softness eased through him. It was as if it was being poured through his veins, slipping through him from head to toe, though he couldn't even twitch a toe.

Her teeth toyed with his scruff, mouthing him, as if she was adjusting her grip on him. Yet, to his intoxicating arousal, he realised that Mercy was laughing at him, even if only lightly. Tonic immobility was a powerful thing and he could not help that he had slumped quite like that, quaking, shivering, just needing her to have him, to hold him.

Even if his arousal was still there, some feeling, tingling and throbbing, returning to his limbs, her teeth leaving his scruff and instead tackling the side of his throat. Her fingers dug into his upper arms, a burst of pain making him moan, though he had never before wanted to lean into a push of pain quite as he did at that moment, head swimming with delight.

It was so crude, so tough... Like he was being beaten up - and yet his dick, quite honestly, had never been harder. Mark had never been kept on the edge for so long before and left still feeling like he could erupt at any moment, his cock pulsing, throbbing, aching desperately. She could have done anything at all to him and he would have accepted it all with thanks, licking his lips even as he shuddered and grunted, the powerful predator above him snarling.

"Yes... Mine..."

Yes, yes, yes... That was all he wanted, shuddering, half on his side, wrenched there as she released his arm and stopped hauling about to pin him again, straddling his hip so that the wetness of her sex ground into it. He relished in how it soaked into his fur, hips twitching, tail trying to flick, though Mark did not really need to. He would serve her again, please her, as and when she wanted it, though Mercy was more than capable of releasing him (or not) as and when she pleased.

Thankfully for the cougar, his sister's need was greater than even his, even though she lavished furious, biting, snapping attention on his neck, his shoulder, leaving marks behind. There were the pricks of her teeth, where the sharp points had sunk into his flesh, but it was as if she was holding back, her tail swinging back and forth, curling and twitching, losing herself right there in the moment.

"Mmmph..."

She groaned into his shoulder, her own rounding, hunching forward, losing herself right there and then. But she needed him, snarling, dragging him onto his back while Mark panted heavily and stared adoringly at her, the cougaress lifting her hips into position.

It took him a moment to realise just where he was, on his back, the mattress soft beneath him even though his body, very pleasantly, ached and throbbed. Pain seemed to make pleasure all the more stringent for how it presented itself and he moaned openly as she knelt on his paws, pinning them under her knees right at his side.

"Yesssss..." Mercy hissed, though it was hard for her not to let her lips quirk in a smile. "You fight so wonderfully... But to have you limp under me too, brother... Mmm. There's nothing like that."

He moaned and nodded, though he liked the other side, yes, very much so, letting her position his hard shaft up at her entrance. The length of his cock seemed like a small treat for her after all that she had done so far, dwarfing him with her muscle, and yet Mercy took it anyway. As was her right, slamming down onto him the very moment that his tip caught in her folds, for she more than knew the limits of her own body.

"Ah!"

She yowled, humping down against him, as if she was ignorant to his need, that he was so close to the edge already. Her dark lips peeled back from her teeth as she snarled, rising and falling on his cock as if it was all that she had wanted. Even though that would not have been accurate, no, not as passion overwhelmed her.

For, while it was submission that Mark longed for, it was domination that sang to her soul in just the way that she needed. And that was just why they fit together just so, Mercy bowing down over his body as she wrenched his arms up, lining up his forearms together above his head, holding him there forcibly.

Not because she had to, of course, but because she wanted to. There was a significant difference.

Mark heaved, head pounding with desire. He needed more, wanted more, though he didn't want to lose himself, no, not yet. Even as his cock throbbed and she viciously attack the front of his throat and shoulders with her teeth, taking on another angle, lusting for it, feeling how his strength faded.

Though she could have merely pressed down on his chest to dominate him and control his breathing, using her weight and strength, she tried a new tact. He blinked, a leather belt sliding around his neck as Mercy held him tightly, pulling it tauter and tauter. His groan told her what she needed to hear as she yanked it tight, cutting off his ability to breathe, gasping, grunting and groaning. She could loosen her hold at any time, but the cup of the leather would remind him of exactly how much control she had over him.

It was all that he needed, to be there before her, even though...he was sure that he could take more. He had to tell her that, his safe word the furthest thing possible from his mind, growling and grunting, lips parted, though she had her right paw on his throat again, gripping and squeezing, watching him intently as he wheezed. She licked her lips and, for a moment, he caught a glimpse of the teeth that had been sunk into him only a moment ago.

His heart lurched.

He needed her.

"If I bite you harder," she hissed huskily, tail sweeping back and forth, "I'll leave scars. Do you consent?"

She loosened her grip on the belt around his neck only enough for him to breathlessly answer, gulping at air.

"Ah... Yes... Yes!"

He cried out as she sank her teeth into his neck all over again, ripping into his body, though she did not cause true harm. Well, it depended on whether one counted a scar as "true harm" or not, though it would not restrict him in any way, not where it was placed. At the crux of her shoulder and his neck, her fangs sank in, biting deeply, tasting his blood, though there was no tender sweep of her tongue up and over the point that she had bitten, not that time.

It was just as well the belt was not a thick one... He wouldn't have wanted, even then with his lungs aching for air, her to lose access to his neck for those bites, no. Not when the leather bit as viciously, the lack of air bringing everything, every tiny little sensation, into stark definition.

There would be a big scar left there and, where it was placed, there was no way that he could hide it. Mark howled and thrust up against her, though Mercy pinned his hips down to the bed with her body, squeezing her thighs around him as if she was a cowboy wrestling a steer to the ground. Even if she didn't need to use brute force against him, she did it anyway - because it made them feel good.

He climaxed inside her as he submitted to her bite, some part of his body fighting back, even as Mercy hissed and snarled at him to stop fighting her. It clearly exhilarated the cougar, however, and he did not feel that she was frustrated at him, so he drove through it anyway, letting bliss swamp him. It was oddly not as satisfying as that marking bite of hers, however, even as she bit again, taking her strong jaws around his right shoulder to leave another deep, crushing, crunching bite there, another scar that he would trace and remember the tale of later.

Maybe the fur would grow back over it enough to cover it, or maybe it wouldn't. Either way, the cougar would revel in the mark that his sister had given him, the claiming, mating bites, how she had fucked him so roughly, so furiously, that anyone might have thought it non-consensual. If not for the consent between them, of course, all that they had agreed to beforehand, establishing boundaries and a safe word.

For Mercy would be Mercy and he would forever be as he was, learning and letting her lead him into the play between domination and submission. The bite shifted, closing on his throat, though that moment was for the cougar female and her alone as he throbbed and bucked his hips weakly, not fighting, just submitting, even as pleasure overwhelmed him.

His vision greyed out at the edges as her jaws, that time, clamped entirely around his throat above the line of the belt, teeth digging in, closing down, restricting him more and more. His chest heaved and his fingers twitched and yet Mark could not bring himself to truly fight back against her, not when it made him feel like he was climaxing all over again, pain tautening in his chest while his throat ached and ached and ached.

Yet it would ache just as much if her teeth were not sunk into his throat, wheezing, squeezing his windpipe so divinely. The belt loosened, her teeth cutting off his ability to breathe, though he still struggled for it, regardless. The body would fight back, after all, even if he wanted to submit everything he had to her and more.

They forgot dinner that night, exploring one another's bodies, though Mark very much felt that he got more of a workout from it than Mercy did. Especially as the sexy, powerful cougar swapped positions on top of him, sixty-nining him with his cock at her lips. He had plumped up, partway, by then, but she was exploring him only, teasing him and thwarting him with his oversensitivity, how delicate his cock was in the aftermath of climaxing just once. Mark didn't even think that he would be able to get off for a second time but he squirmed and kicked and fought until she growled at him.

"Stay still, brother."

There was a delicious "threat" in her voice, the kind of threat that he wanted to see just how far she could go with. Yet the cougar merely pinned him once again with a knee on his chest, bearing down into it until he grunted and wheezed under her weight and muscle. She knew just where to press down to exert the most pressure, his eyes rolling from the air deprivation, though he squeezed her legs reassuringly. He would have done something to show her that he needed a break if it came to that, though that was not something that ever came to light. Not that first time together, not that night, not as her rough tongue pleasurably tormented his oversensitive cock, the throbbing ache of it locking him in place as much as the physical restriction of his body did.

He doubted that there would ever be a need for bondage when it came to Mercy... She had come into her own and all he could do was squirm and pant while she forced a broken kind of orgasm from him, even if it had him swimming in mindless, softening submission. Dimly, he was aware of his tongue lavishing attention on her clit, circling and lapping and flicking up and down, bringing her to climax, though she had sat on his face for that one again, facing back down the length of his body.

His chest shuddered, once again able to ease air into his body, dragging and scraping at it. She could have him, his scruff aching, wanting again her teeth at his throat, the pressure of her teeth clamping down, even cutting off his ability to breathe with her jaws for longer, perhaps even edging him. There was much to be explored, though the cougar took the time afterwards with him.

After all, she had hurt him and her fingers could be just as gentle on him, sitting him up and checking him over, ensuring that her bruises had not done any lasting damage. As much as he might have wanted those permanent marks, it was clear that that was something that Mark was going to ask for.

Unless it becomes a part of your agreement.

_ _

But that was something that he was going to have to discuss with her first - and deal with another day. It was too much to go into right then, even as Mercy talked to him and rubbed his shoulders where her teeth had not sunk in, tending to the cuts and even praising him for holding up to her brutality so well.

"You did wonderfully, brother... I never imagined that you would be like that, and with me."

She kissed his lips softly, soothing the bruises there with her tongue, and he moaned into her touch, eyelids fluttering, coming back to reality. Everything hurt a little more when he swam away from sub-space, yet he had to come down from that beautiful high sooner or later, to let her take care of him.

She held a straw to his lips, bidding him to drink water and, afterwards, to nibble on a snack bar, just to make sure that he regained his strength. But his sister was there for him the whole time, even if he didn't want to eat, with a warm, caring smile, drawing him in snugly to her arms and her body, though, that time, she did not squeeze him hard enough to hurt.

Aftercare too was just as important as rougher play itself. That was something that Mark was yet to learn.

But he had her to take care of him. All as he languished in slumber, needing Mercy to draw the bedsheets over him as he drifted off. Mark, however, no longer had to hide how his eyes lingered on her form, how he admired her strength, her obvious power, not when such changes and a shift in the balance between them had already come to pass.

His body ached fiercely. And, still, the cougar slept with a smile on his muzzle, his tail longingly laid out over his sister's thigh.

The next day dawned bright and the siblings emerged from the camper van yawning and rubbing their eyes, even though Mark was back in an oversized T-shirt of Mercy's and the underwear he had been wearing the day before. He would need a shower soon, but Mercy stretched out her back with a crack and a grin, glancing over at him.

Mark knew that he was worse for wear, his fur ruffled up in the wrong direction in places, needing a good brush from head to toe. The bite mark at his throat was the most obvious, though he had cleaned it up some, even if it would not stiffen and tighten too much over time.

The relationship between them, of course, had been forever changed and, even then, he did not know where their time together would go. They had a lot to talk about with the raunchy evening of sex that had spun out between them and the lust that had been building before, what had simmered and been stoked right up into a full-blown fire... Yet that could come in time.

"Let's get breakfast, brother."

Mercy grinned, nudging his shoulder and laughing aloud from sheer delight when he flinched and groaned. To leave marks like that... It made her genuinely warm all through, comfortably sated on all fronts. He was still sensitive, of course, and was going to be until the bruises settled down again. The funny thing was that, with Mercy, he didn't think that he ever wanted to be without those bruises ever again. And if she was willing to leave even more permanent marks on him, with her teeth and claws too, that would be something that Mark would be very much willing to explore.

In their changing dynamics, the illicit nature of their relationship, there was much left to be explored...