Another full day
Billy scratched the underside of his bright gut idly as he searched the freezer for another carton of ice cream. The big lantern tiger had gotten a lot bigger since moving in; lately, with his master's encouragement and a steady supply of food, he was weighing in at just over four hundred pounds...under normal circumstances. Spoon in hand, he was just about to embark on some Rocky Road, when he turned and saw his master, shirtless as usual, standing in the doorway. The wolf was big in his own way, firmly muscled under a pelt of blue fur and nearly half a foot taller than the tiger.
"I wasn't expecting you home so soon, Sir," Billy said, putting down the ice cream and standing at attention for his master. "How can your tiger serve you today?"
The wolf took his tiger's paw and led him up to the main room, where a distressingly large array of food was laid out around the bed. "It's feeding time, tiger."
The tiger's light flickered somewhat with uncertainty, and he rested a paw on his gut to show how stuffed it was. "I couldn't possibly, Sir... I've been eating all day... I'm sure I'd burst a lot more quickly than you'd like..."
The wolf shook his head. "Don't give me excuses, tiger. Besides, this food isn't for you, it's for me."
"What, Sir? I couldn't..."
"You told me," the wolf said pointedly, "all about your feeding fantasy, and how you wanted to stuff someone to his limits and further. Today's your day."
"Sir, I..." The shy tiger tried to continue protesting but shook with trepidation, his light dim and guttering. "I..."
The wolf gripped the tiger's jaw and forced it upward, making him stare into his fierce red eyes, weakening the tiger's will. "You are mine and you obey me."
The tiger had been controlled by the wolf far too many times to put up resistance. "I am yours and I obey you, sir."
"It's a servant's job to feed his master," the wolf said, his gaze locked with the tiger's.
"It's a servant's job to feed his master," the tiger repeated.
"Nothing is more important to you. You want to fatten your master more than anything else in the world."
"Fatter than anything else in the world," the tiger said.
The wolf released Billy from his immediate control. "Time's wasting, tiger. You've got a job to do." He got up on the bed. The tiger looked around for something to start with, and his eyes and gut lit up as he saw a few lengths of rope on a shelf. The wolf smirked a bit as his legs and arms were tied to the bedposts, knowing that it would take a lot more than rope to really hold someone with demonic aspect, but he decided not to point this out.
Billy grabbed the nearest dish of food--something savory with potatoes--loaded it on a breakfast tray, and straddled the wolf's belly, setting up the tray over his chest, his master looking up at him in mild amusement. The chubby tiger sat down slowly, till his full weight was on the wolf's abs, and dug in with a serving spoon. "Open up, sir!" he said brightly.
He started feeding his master eagerly, shoving in two or three spoonsful at a time before letting him chew, never letting him swallow the whole mouthful before adding more. The demon-wolf's metabolism made short work of the dish, very quickly converting it to a thin, hardly-noticeable layer of fat over his whole body--maybe five pounds' difference.
Undaunted, the tiger tossed the pan aside and reached for another dish--a thick, heavy lasagna--setting it on the tray and going to work on feeding it to his master, this time taking big chunks of it in his paw and stuffing it in the wolf's face. But after only a couple of mouthfuls the wolf started refusing the feeding, his jaw firmly clamped shut. He swallowed while the tiger looked down at him, perplexed.
"Tiger. Cock. Here. Now." Billy rushed to put the breakfast tray aside at the sound of the impatience in his master's voice, and scooted forward, the slightly-damp bulge in his red briefs--the only clothing allowed to him--soon in his master's face. The wolf took the cloth-covered bulge into his muzzle, running his tongue along it a bit before sliding it into the Y-front to join the tiger's dick, which was soon poking through the opening directly into his maw.
Billy leaned back and shut his eyes, enjoying the feeling of his master's muzzle on his dick. The wolf took the opportunity to free himself from one of the ropes holding him down and grabbed the tiger's balls, sending a bit of his power into them. "You're gonna cum like otter today," he said, around a mouthful of cock.
The tiger yelped, his light flickering as he was brought to sudden orgasm and a gardenhose stream of glowtiger seed started pouring down his master's throat. He moaned at the feel of the cum building up, churning inside him, faster and faster, his cock trying hard to keep up with releasing it all. He could feel his master swallowing around his cock and his tail lifting slowly as his master's belly swelled underneath it. The wolf's body went to work digesting the cum at a rapid rate, fat accumulating all over his body, just fast enough to notice, and Billy looked down half in concern over his powerfully-blasting cock and half in satisfaction at his master's slowly-fattening face.
Minutes passed as the wolf held the tiger in place, gulping cum from his cock and getting fatter, now twenty-five, now fifty pounds heavier than when he'd begun. The tight boxer-briefs the wolf wore strained to contain the additional inches to his waistline, the increased girth of his thighs, the swelling roundness of his rump, and the firm power of his erection, but at seventy-five extra pounds of weight the underwear began splitting at the seams slowly up his legs and suddenly at his ass, and at a hundred extra pounds the stretched waistband finally gave way with a loud snap, the rest of the fabric quickly coming apart, leaving his proud maleness free, jutting upward into the air.
He squeezed the tiger's cock with a touch of power and the flow from it stopped, as suddenly as turning off a faucet, though he could still hear the cum churning into existence inside his tiger, causing him to swell slowly with denied release. The fattened wolf tucked Billy's still-hard dick into his briefs and grinned. "Tiger. On my dick, now. And get back to stuffing me."
"Yes, sir!" Billy said, happy enough his dick hadn't been destroyed by the cumflow that he didn't notice the subtle swelling in his gut from the cum backfiring into his system. He scooted back over his master's heavy gut and slid his master's thick cock between his natches, purring softly as it pressed into his tight eager hole. Once he had it in him to his full depth--and he'd taken a second to get used to it--he reached over for the breakfast tray again, set it up in front of him over his master's chest, and resumed stuffing him with handfuls of the lasagna. Every time he leaned forward to cram food into his master's maw the cock in his ass slipped mostly out, and every time he sat back to pick up more his ass swallowed it to the hilt. Billy had nearly fed the wolf all of the lasagna before he noticed the swelling in his own body that had been going on--the fat tiger's gut had grown till it had hit the breakfast tray. He put one hand on his glowing gut, feeling it firm and sloshing with liquid inside, and looked down at his master. "Erf... Did you cum already, sir?"
The wolf caught his gaze and smiled one of those smiles that always made the tiger's belly dim with fear. "No, tiger. You did."
"I what?"
The wolf's eyes took control of the tiger's mind again. "Sit still. Enjoy it. You love feeling so full and firm and round. You love to swell until it hurts. You love to burst your limits..."
"I love to burst, sir," the tiger repeated numbly.
"There's a good tiger..." The wolf released his control and started thrusting into the growing tiger's rump, enjoying the slick tailhole.
The tiger leaned back, taking it deep, one paw rubbing over his bright gut as it continued to fill, precum leaking through his briefs. "I love feeling so full and firm and round, sir!"
The wolf ignored him and continued focusing on thrusting deep into the tiger's cum-filled bowels, watching the tiger's body inflate inch by inch. Very soon he heard the strain of fabric and Billy's underwear, too, busted apart from the pressure. The tiger began to wince, tears forming at his eyes as his growth began to become painful, his cum-filled innards pushing his body out much farther than it was designed to. Even as the tiger's body reacted in pain, his mind still remembered his master's command... "I love to swell until it hurts," he repeated, one hand on his hard dick.
The wolf chuckled some and started thrusting upwards into his tiger harder and faster, watching a network of stretch marks form as the tiger's gut grew and grew. When he heard the ominous tell-tale creak of the tiger's hide being stretched to his limit, he slammed his cock deep inside and panted, adding his load to the sea of cum already built up inside. Two seconds later Billy's light went out altogether and his torso exploded, scraps of tiger going everywhere and a torrent of glowing seed flowing out and covering the wolf, the bed, and a good deal of the floor.
The fat wolf panted from the exertion of orgasm for a few moments. As soon as he caught his breath, he reached for the last bite of lasagna and swallowed it down, rubbing over his cum-covered belly softly. He felt rather sleepy and rolled over, soon dozing with his new belly still cradled in one paw. There'd be time enough for a second round later.