The dog and the horse
The canine leaned back, peeking past the hood of the car at the rest of the parking lot. So far, since the morning bell had rung, it was empty of any of the other students. In front of him, the stallion rocked his hips against the canine's cock buried deep inside his ass. Groaning softly, the canine turned his attention to the stallion on all fours in front of him that he was leisurely humping into.
"Oh fuck dude... we're finally alone... nnf. Fuck you've got an amazing ass," the canine said. His fat red dick plunged in and out of the stallion's stretched anus, the fat knot at the base of his cock bumping against the stallion's hole over and over. Between his legs, the canine's bloated balls, swollen thick with a week's pent up load and made a lot more dense thanks to some special tonics he picked up, swung back and forth to slap lightly against his thighs.
The stallion whickered out softly, his ass lifting a little higher in the air, his tail flagging gently with each slap of the canine's hips against his own. Soft, chestnut brown fur cushioned around the canine's dick, brushing along the length each time the fat cock slid out of the stallion's ass. He whined just slightly, relishing the sensation of being fucked. With a flick of his mane, he lifted up slightly, thick, powerful arms stretching and a broad, muscled chest flexing slowly as he rose. A little groan escaped his lips just as his dick, a good foot of equine meat mottled with white and pink splotches, began to thicken and flare. Huffing slightly, he moaned out, "Ohhh fuck man. I think I'm gonna cum... oh god I can feel it."
Just as the stallion clamed a hand over his mouth to hide the whinnies of pleasure from his spasming cock, the bloated bell flared outwards while thick ropes of heated equine semen splashed against the ground. Behind him, the canine winced just slightly from the way his equine fuck buddy tensed around his dick. The thrusting motion from the stallion grew in pace, humping hard back against the canine with each thrust while he rode out his orgasm.
Feeling his knot beginning to thicken, the canine muttered out, "Unh... shit... I don't think I can hold out much longer. You sure you want me to pop you? All I gotta do it put my knot in and you're paste."
Looking back at the canine with wide, eager eyes, the equine nodded and moved his hand from his muzzle, just slightly, "Yes... oh my god yeah dude. I totally want you to pop me. Now put it all the way in and splatter me good!" The stallion thrust back against the canine with a rough push of his hips, teasing the canine's thick knot with entrance to his already stretched out ass.
Gasping at the sensation of hot, tight stallion ass around his dick and the admission of the stallion's desire to get burst like a used condom, the canine thrust forward hard, wedging his knot against the stallion's tight pucker. The bulb of canine knot had already started to thicken slightly, but hadn't ballooned out just yet, so it took the canine a moment of working his hips to pop his bulb into the stallion's ass. When it finally slipped in past the tight ring with a thick, wet squelch of flesh, the canine's hips slammed forward against the stallion's ass.
That was all it took to make the canine's knot bloat outwards. Gasping sharply, he grabbed the stallion's hips and began to hump in earnest, slapping his hips against the stallion's ass in short, rapid thrusts. Whimpering out and trying to keep his own noise level down, the canine muttered, "Here it comes man. Ohhhh fuck here it comes. I'm gonna bust a nut so hard in you!" With a sharp jerk forward, he tensed just as his dick gave a spasm and his nuts a jump, then with a low moan and a tremble, the canine came. His load flooded out of his dick, stretching it thicker and wider on the flow, and punched its way into the stallion's guts.
The first wave was nearly a gallon, and the heated load made its presence known inside of the stallion at a rapid pace. Almost immediately, the stallion's belly domed outwards, pushing down against his still spurting equine cock. The load backed up rapidly inside of the stallion, spreading through him. In moments, his belly had swollen to look like he had eaten a large melon, but it kept growing. As the canine kept his hips snuggled to the stallion, more and more cum flooded into the bulky, handsome male.
Grunting out a warm breath, the stallion moved a hand down to feel his belly and the pulses of cum behind his skin. "That's it man... that's it... bloat me up and pop me good and hard." He groaned out that last whine his fingers sank against his expanding flesh. The stallion's stomach wasn't the only thing that grew, though. As the canine's orgasm continued, more and more of the stallion began to swell.
As his belly began to bloat, so did his chest and his ass. The stallion's sides slowly pressed outwards, joining his belly in rounding, then his chest got into the act as well. The thick, toned pecs sagged at first, then thickened and swelled, growing like a pair of tits atop the male's expanding torso. His belly, now as large as a beachball, cushioned down onto his dick while his chest started to push down against his belly. And behind, the canine watched as the stallion's plump ass began to bloat, swelling like to cushiony balloons around his dick. He grabbed those growing brown orbs, squeezing and stroking them to feel the way they went from toned muscle to softly bloated cum balloon. The sensation of feeling his partner distending and bloating on his load only made the canine hump in harder against the growing ass.
The thrust made the stallion whine out in breath, gasping sharply as the flow spread more and more through him. As his arms began to thicken, he moaned out in a slightly gurgling voice, "Duuude... I can feel it. It's sooo much.." While his muscled arms lost their definition and began to grow as thick as his legs, the stallion's dick and balls got into the act, each starting to bloat outwards. The huge rod, already spent moments ago, began to leak spunk once more, then spurt it, and as his dick swelled outwards, turning into a log, the cum from its tip flowed in a more steady stream. Laughing, the stallion said, "I'm cumming your cum, dude!" A happy squeal came from him just as he felt his growing, sagging balls brushing in against the ground.
The canine nodded, grinning to his partner, "Nnnf... won't be long now and you'll just be a big cum splatter on the ground. Ohhh... hope you're enjoying it, 'cause it's the last thing you ever will!"
That statement made the stallion cry out in pleasure once more, though his voice was much thicker with the weight of cum behind it. As his throat stretched out growing like the neck of the condom he had become, the stallion slumped against his massively cum bloated torso. It had almost rounded out now, the distinction between chest and belly swollen away. Gasping, panting, he moved his thickening hands to his face to watch his fingers suddenly expand with little fwoomps, each turning into fat little sausages. He pressed them to his cheeks, whimpering out tenderly, "I can feel it... getting so full." Saying that, the stallion's cheeks pushed outwards, puffing up.
As his head started to swell, the stallion's legs were reaching a state that made them look as big as tree trucks. Thick and swollen, the corded muscle now disappearing in a wave of spunk, the stallion's entire body had almost completely swollen. The canine gave his rump a smack, "Almost there... almost there... come on baby... pop good and hard for me."
Groaning and gurgling, though more gurgling than groaning, the stallion's head suddenly distended, growing outwards thick and rounded, his features puffing out, even his floppy ears growing bloated and rounded. A quiver ran through the stallion's body as the sensation of being packed so full of cum raced through him. He knew that in moments he'd cease to be, burst into a thick splatter of cum on the ground, but the thought and the sensation made him quiver with desire. The feeling grew inside of him, changing from a fullness to a tightness that stretched through him. He could feel his body straining to hold together, to hold all the cum back, but he wanted that final, blissful release, and the canine gave it to him with a last hump and a gentle moan. A final blast of spunk flooded into the stallion, and with a thick BLORP, he exploded, disintegrating into a massive bubble of canine spunk that suddenly spread out across the ground with a splashing wave.
With a soft yelp, the canine landed forward into the huge puddle to watch it spread out, the last remains of his partner. Smiling, though, he straightened up and pulled a towel from a plastic baggie. Wiping himself off and clearing the cum from his fur and feet, he slipped into another nearby car to get dressed. Then with a wag of his tail, he went to sneak back into class while the cum puddle that once was a stallion flowed downhill towards a rain gutter.