The next morning, Rumble woke up with his sleeves hanging over his hands.

He didn’t think much of it, at first. Maybe he’d done something funky with the dryer, or maybe he’d just stretched them out or something. It wasn’t until he went to go wash up and realized that he had to stand on his tiptoes to reach the shelf holding his toothpaste that something felt off.

At six and a half feet in height, a big, broad Rumble had taken great pleasure in making use of his size in every way possible. Now, though, he had to reach up, straining for his toothpaste over the edge of the top shelf of his cabinet. He managed to get it down, of course, but only after blindly feeling around for a few seconds. Just days before, it would have been at eye level.

As he got dressed, his feeling of unease only grew. His shirts were so much baggier than he remembered. Fabric that had bulged with his musculature now sagged over his chest; broad, heavy pecs had been replaced by a merely “toned” chest. One of his favorite shirts—a muscle shirt that had just barely reached his belly button—now fell down over his crotch.

With a stallionhood as thick as his forearm and nearly two feet in length, it had been years since Rumble had woken up without a throbbing morning wood, especially after a night of no sex and just one measly orgasm. But where usually he’d be ready to cum buckets before showering, today his twelve-inch cock stayed flaccid. His usually pent-up balls felt merely halfway full, as though his measly display last night had left him satisfied. One look at his shrunken package made Rumble glad to cover it up with a pair of pants.

Except his pants wouldn’t stop falling down. Where a broad pair of muscular hips and a protruding bubble butt had held up his size-38 waist just seventy-two hours before, Rumble’s pants now refused to stay perched around his increasingly slender waist. Rumble’s lips were quivering as he tightened his belt around his waist to the maximum setting. A good six inches of fabric fell over his ankles; he’d had to roll them up so that he didn’t look like some kind of child swimming in his parent’s clothing.

It didn’t help that he couldn’t even wear his boxers, his XL-sized underwear refusing to stay up where a bulging pair of thighs and a massive cock-bulge had kept them in place previously. It was only a pair of briefs, several years old and only used when he really wanted to show off his “size” that managed to stay on without any trouble. Of course, now, they didn’t really do much to show off his much-smaller stallionhood.

In a daze of confusion, frustration, and denial—this couldn’t be happening; it was all in his head; his clothes had just stretched in the wash or something—Rumble set off downstairs. Instead of groaning beneath the weight of a massive muscle stud, they merely creaked beneath the footfall of an average-sized stallion.

Pipsqueak was in the kitchen already. From the army of smells that assaulted Rumble’s nose as he walked in, his roommate was really cooking up a storm.

Pipsqueak glanced over his shoulder. “Oh, hey,” he said casually.

That morning, Pipsqueak had woken up feeling like a million bits.

He’d bounced out of bed, though his knees had jarred a bit when they’d hit the floor about six inches earlier than they’d been used to. Still, he couldn’t help eyeing his new, bigger body in the mirror when he got up. It felt good being bigger.

Things that had been out of reach were suddenly in grasp. The shower head suddenly loomed in his vision, rather than towering far above him. He actually enjoyed his shower, watching the hot water stream down his thickening muscles, longer legs, and bigger cock with a mixture of lust and awe. He’d jerked off twice to his reflection in the mirror, and had been both proud and mortified at the size of the resulting mess.

His clothes had been feeling smaller for the past few days, but it was only when he got dressed that Pip realized how tiny they actually were—how tiny he’d been. And how much bigger he was now. Measuring himself by the marks on his bedroom wall, he found himself to be just over six inches. A tingle ran through his spine when he did a quick calculation and realized that Rumble would be just a little bit taller than him. Heck, they were almost the same size!

Wearing a pair of jeans that were starting to look more like shorts, and a shirt that barely came down to his belly button, Pip thumped down the stairs. His new, heavier muscles made the staircase shake with every pounding step he took. Though he wasn’t anywhere near huge (yet), he loved the fact that he was no longer short enough for school-age colts to look down on.

He all but danced his way into the kitchen, loving his new, taller perspective on things. He could reach the top shelf of the fridge without reaching! The carton of milk no longer needed both hands to lift! He quickly set about to preparing a sizeable breakfast for himself—seven strips of bacon, a whole grapefruit, and a four-egg omelette. Most ponies of his size didn’t eat that much, admittedly—but most ponies of his size hadn’t grown six inches in forty-eight hours. Pip’s stomach was a roaring abyss by the time he got the bacon going in the pan.

Hearing footsteps behind him, he turned and grinned. Rumble, clad in clothes that were clearly far too big for him, had slouched his way into the kitchen. A baggy t-shirt that looked like it could have belonged to his father was draped over his shoulders.

“Oh, hey,” Pip said.

“G’morning.” Rumble noticed that he and Pip were about eye level, and quickly sat down, averting his eyes. “That smells good.”

“Doesn’t it?” Pip said. “I’d offer you some, but I think I’m going to eat it all. I’m a growing stallion, you know.”

“I, uh,” Rumble said, faltering. “I wasn’t really that hungry anyway.” Just last week, he’d have been more than happy to consume a second breakfast—or even a third, just to fuel his massive body and muscles.

“More for me,” Pip said happily. He turned back toward Rumble and thumped a fist on his chest. “What do you think?”

“Huh?”

“Me, of course,” Pip said. “Bigger and better than ever. I can see why you like it.”

“Right,” Rumble said. “Yeah.” His eyes darted over Pip’s larger form—not as tall as his, admittedly...yet. But standing up, they were almost of equal height: the tiny little shrimp and the big, proud stud. He shifted uncomfortably in his chair. How was this possible?

He noted the other stallion’s shrunken-looking clothes, and his new toned muscles. Pip must have been roiding out at the Shake Shack, Rumble guessed. They tried all sorts of crazy formulas over there. Maybe some unicorn had signed up to work as a potion maker.

“I’ll have to be honest,” Pip said. “For the longest time, I wondered what it’d be like to look down at other ponies, instead of up.” He grinned, and gave his arm the lightest of flex. His too-tiny sleeve bulged obscenely around his bicep, the once-loose fabric straining. “You were right, Rumble. I’m sure looking down at other stallions is a bit of a rush.”

“Yeah.” Rumble glanced up at the clock as Pip brought his breakfast over, enough food to feed a family of three. “I, uh, have to go to work.”

“Okay,” Pip said through a mouthful of food. “See you later!”

The next eight or so hours were an experience for the both of them.

Suddenly, Rumble found his job a lot more difficult. Heaving heavy sofas had been a breeze when thirty-pound weights made for a “light warmup” in the gym. With a small, thinner body, though, he had to struggle to get his end—his end!—off the ground. Where he’d once managed to carry a loveseat out on his own, he now had to get his boss’ help to get it out of the door. Old Ink Pen just gave him an odd, sort of pitying look, and helped him move the latest order outside.

The other stallion was actually able to look him in the eye! Rumble found his face growing hot as he struggled to fit this new reality with the height he’d lived with since puberty. This wasn’t right. He should be towering above everypony else, muscles flexing through his sleeves as he moved couches without a sweat.

Meanwhile, Pip was having the time of his life. Mares visiting the Shack who would have passed him by at any other time actually seemed to respect him. For so long, he’d had to live with people looking down at him, not only physically but socially too. Now, though, most mares had to look up at him, and most stallions met him eye-to-eye. He could feel their gazes on his new, larger body and couldn’t resist flexing slightly as one mare eyed his bicep. She chuckled and moved on, shake in hand, but Pip couldn’t resist promising himself: Tomorrow, she’ll get an even bigger show.

And he could feel it. The amulet was warm against his chest, and every hour or so, Pip gave a little grunt as the feeling of growth spread throughout his body. His limbs stretched out a little farther, his muscles swelled a little thicker, and his too-small clothes got even smaller. On the way home that night, he picked up a new pair of shorts and a shirt more befitting a stallion of “his” size.

By the next night, of course, he’d already outgrown them, too.

For Rumble, the two days passed like a blur. Both mornings, he woke up a little smaller, a little weaker than the day before. By the end of that day, he was down to five-foot-ten.

The moment that Pip realized that, for the first time ever, he was looking down at Rumble, he felt a surge of warmth in his chest. He double-checked his height that night and had to restrain his glee. He measured six-foot-three from head to toe.

Bigger and bigger. That’s what life felt like for Pip. Every day, his arms flung out a little longer; his muscles got a little bit thicker; and his bulge got a little bit heavier. It was almost amazing the first time he realized that he did have a bulge, his flaccid stallionhood protruding noticeably in front of his crotch. It wasn’t much at first—just a half inch or so—but he could cup his heavier balls through the front of his jeans, could feel his longer, thicker shaft snaking down his leg.

The problem was, of course, that even his new, bigger clothes didn’t fit him anymore. The morning that Pip woke up and realized that he was six-foot-five, just an inch under Rumble’s starting height. His new shorts didn’t even reach his knees. His old shorts looked like a child’s compared to him.

Just like Rumble was starting to.

At five feet and six inches, the “new” Rumble was almost as short as Pip had started as. Most mares looked him in the eye; most stallions looked down on him. He’d left work in disgust after he’d found that he could only lift a sofa’s end two inches off the ground before his arms were weak with the exertion. When he’d gone on break to take his customary self-pleasuring session, he’d found that all his arousal vanished when he caught sight of his paltry, five-inch cock.

How could this happen?

Fortunately for Pip, Rumble was still too dazed to come up with an answer for that question. So, when Pip came down the next morning, just an inch shorter than Rumble had been and wearing a very familiar jersey, with a very prominent bulge snaking down his pant leg, Rumble found his jaw hanging slightly open.

“That’s—that’s my shirt!” he said, looking up at his bigger roommate. “And my pants!”

Pipsqueak at least had the grace to look somewhat embarrassed. “Sorry,” he said, shrugging. “None of my clothes fit. I mean, it’s not a surprise, really—not many clothes can contain this sort of body.” He flexed a bicep and bounced his sizeable pecs a few times. “So I decided to borrow yours. It looked like you didn’t need them anymore, after all.” He gestured to Rumble’s clothes, and the smaller stallion almost choked when he noticed that he was all but swimming in his clothes.

With a muscular waist turned slender and a pair of arms less bulky than downright weedy, the shrunken stallion was drowning in his old clothes. Rumble’s cheeks flushed, and he did his best to sit up straighter in his chair—which only made it worse when he realized that he came up to the middle of Pip’s toned six-pack.

“They’re a little loose,” Pip said, with another shrug. “But I figured I’ll grow into them.” He grinned down at little blushing Rumble and ran his big hands down his flexing chest. “Mm. Might even grow out of them.”

Poor little Rumble had no response to that.

“Anyways,” Pip said, turning away, “you’re welcome to wear some of my old stuff. It should fit you.”

“Thanks,” Rumble mumbled. Pipsqueak waved and left, leaving Rumble to stew in his chair. His dangling legs still reached the floor, at least, but just barely.

He should go to work. But he didn’t want to go in, not to see his boss eyeing him with pity as he struggled to lift even the smaller pieces of furniture. No, he decided; he’d go to the gym. Maybe whatever had happened to him was reversible. Maybe he could work back some of his gains.

Unfortunately, the only thing he felt when he got into the gym was awkwardness. Everypony who’d known him couldn’t help but do a double-take at his smaller, weaker stature. The once-stud now had to wade through a sea of muscle and size that all but towered above him.

He tried his previous warm-up weights, just on a note of optimism. He couldn’t even get them off of the ground. A pair of fifteen-pounders proved moveable, but just barely. Finally, his cheeks coloring in a bright red, he picked up a pair of five-pound weights that he hadn’t used since foalhood and went off to lift in a corner alone.

It didn’t help, of course, when he caught Pipsqueak out of the corner of his eye. The big and growing stallion was easily lifting a pair of forty-pound weights above his head, his massive biceps flexing with every pump. Every eye, it seemed, was on the newcomer, his chest wider around than all but the most committed bodybuilders.

Fuming, Rumble threw his weights down and stalked out of the gym. It helped even less when some dumb lifter noticed the sway of Rumble’s wider hips and slender waist and let out a shrill wolf-whistle. Rumble turned and glared, and the stallion, noticing Rumble’s still-masculine face, blanched.

But there was no denying the newborn fullness to Rumble’s lips, or the way his hips spread a few inches out from his slender waist. With a muffled snarl, Rumble turned on his heel and stalked out—though he didn’t fail to catch a glimpse of Pipsqueak’s flexing muscles and chest on the way out. If anything, the other stallion looked even bigger than he had just a second ago…

Rumble fumed all the way home.

Rumble felt Pipsqueak before he saw him.

He’d been sitting on the couch, staring at a wall while mindlessly rubbing his crotch. It was hard to miss the sound of the key in the lock, or the sound of Pip’s “I’m home!” It was even harder, though, to ignore the vibrations that Pip’s footsteps sent through the floor of the house. Rumble had never noticed making that much noise when walking around when he’d been that big...but then again, to a six-foot-six, two-hundred-eighty-pound stallion, lots of things tended to go ignored that littler ponies might pick up on.

Pip stepped into the room, Rumble’s clothes proudly displayed on his body and fitting him like a glove. Since that morning, he’d filled them out rather nicely, his big, round pecs straining against his sweat-stained muscle shirt and his biceps bulging against his shirt sleeves. Rumble watched the slightly bouncing bulge at Pip’s crotch and, almost unconsciously, gave his own a little squeeze.

“That was a fantastic workout,” Pip said, grinning down at his smaller roommate. “I can see why you liked it.” He struck a pose, flexing a thirty-inch arm with a fierce grin. “Gives one a real sense of power and size.”

“Yeah,” Rumble mumbled. He was too busy watching Pip’s arm bulging as his own pitiful “bulge” swelled in his pants. He definitely wasn’t gay, but he could definitely appreciate a good body. And somehow, Pip’s new scent almost appealed to him: a masculine, sweaty kind of musk that filled his lungs with its sheer virility. Before Rumble even realized it, his dick was hard and throbbing just from eyeing Pip’s incredible—his former—physique.

Pip’s grin widened. One big hand strayed down to his crotch and gave his enormous bulge a quick squeeze. “Looks like it actually turns me on quite a bit,” he purred, his other hand tracing along the curves of his perfect six-pack. His massive cock throbbed in his pants; Rumble stared as he saw a visible line of dampness flowing down Pip’s pant leg. “Think you’d care to go for our usual post-gym ‘workout’?”

“I—oh!” Rumble said. He covered up his own stirring crotch and blushed. “Maybe not tonight, Pip. I’m feeling a little”—small—”tired.”

“I didn’t mean you,” Pip said, casually. “After helping you out so many times, I figured that it might be time for you to return the favor.” He thrust his muscular hips forward, and chuckled when he saw his sizeable bulge bouncing against his thighs. “What do you say?”

Rumble eyed Pip’s larger body: his massive, flexing pecs; his incredibly broad shoulders; his big, veiny arms; his towering legs; and, above all else, his absolutely monstrous bulge. Licking his lips, Rumble realized that, between Pip’s musk and size, there was no way to say “no” here. “Sure,” he said. “I guess.”

“Excellent.” Pip plopped down on the couch beside Rumble, shoving the poor little stallion off to the side. Pip’s big, muscular ass took up more than a full couch cushion, leaving Rumble a bit squished. He grinned down at the smaller stallion, whose slightly more effeminate face only came up to Pip’s heaving pecs now, and hitched his fingers inside of his shorts.

Pip loved watching the size of Rumble’s eyes grow as he slowly unveiled his monster shaft. “Nice and big, right?” he said. Now Rumble finally knew what it felt like to lay eyes on a dick as long as his arm, with balls bigger than his fist. Especially at his new, smaller size…

“Yeah,” Rumble breathed.

Pip beamed down at him. “Well?” he said, kicking his shorts and underwear off. His erection throbbed, slowly reaching its full size of eighteen inches.

Rumble swallowed and, his hand shaking, reached out. Pip’s shaft felt impossibly huge beneath his palm; he had to use both hands to reach all the way around. Pip savored Rumble’s first few awestruck strokes, but soon seized on a much juicier idea.

“This,” he grunted, picking up Rumble as easily as he might a child—which Rumble might as well be to him now, over a foot shorter than him—“Might be a bit more fun.”

Rumble let out a yelp as he suddenly found himself in Pip’s much larger lap, straddling the bigger stallion’s dick. His shorter, skinnier legs draped over Pip’s tree-trunk thighs like matchsticks. He could feel Pip’s bulging pecs rubbing up against the back of his head.

“Well?” Pip said again. Rumble took a moment to acclimate himself to his new surroundings, and then got back to work.

Pip groaned happily as Rumble’s slender hands went to work on his massive, throbbing crotch. It wasn’t long before Rumble felt a heavy weight on his newly curvaceous hips, then further, onto his slender, full legs as Pip eased the smaller stallion’s pants and underwear off of him.

“No,” Rumble grunted, still struggling to contain Pip’s massive erection in his hands. “Don’t look—”

But it was too late. Pip smirked down at Rumble’s paltry little four-inch boner. “Looks like you’re enjoying this as much as I am, little guy,” he said, giving it a little pat with a finger even longer than Rumble’s whole dick. “Let’s make this a little more fun.”

Rumble bit down on a moan as Pip easily took his whole package between his thumb and forefinger, their combined stimulation enough to send him soaring towards a peak. Meanwhile, Pip just groaned and jerked his hips lightly as Rumble worked the larger stallion’s shaft for all he was worth.

“Mm,” Pip grunted, feeling the amulet heating up against his chest. The physical contact was already at work; without Rumble knowing it, he’d already shrunken to below Pip’s original size, leaving him at five feet and four inches, and Pip himself at six feet, seven inches. Pip happily flexed his chest, feeling his impressive and growing pecs strain against the suddenly tighter shirt. Suddenly, Big Rumble’s clothes didn’t seem quite so big anymore…

Rumble let out a soft cry as he came, his shrinking package small enough to be pleasured by just two of Pipsqueak’s massive fingers. A few drops of cum landed on his stomach...and then that was it.

The sight of just how small Rumble had become, the sight of just how huge he was now, especially compared to the two tiny hands rubbing along his shaft, was what set Pip off. He started off with a growl, which heightened into a moan as he reached the edge—and came.

His cock jerked and leapt wildly in Rumble’s grip, blasting rope after rope of thick, creamy cum into the air. They splattered against Rumble’s face, some going into his mouth, and others going past him to land on Pip’s swelling chest, or even the wall behind them. Meanwhile, the skin contact just sent Rumble growing even further, his whole body hulking out as his orgasm washed over him.

Six foot eight. Six foot nine. Six foot ten. Up and up Pip grew, his upper body straining against Rumble’s shirt until fibers started to pop. More muscle definition until just one of his arms was wider around than the shrinking Rumble’s entire torso. Six foot eleven. Pip’s cock was still growing in Rumble’s grasp, reaching twenty inches without breaking a sweat.

Rumble himself was shrinking—five foot three, five foot two, five foot one… His cock was getting smaller. His mane was growing out behind him, his muzzle softening as his hips widened and his waist tapered into an hourglass shape. He felt something thumping against his chest and found he couldn’t move; Pip’s huge, spasming erection had pushed against him, trapping his small, slender body between Pip’s boner and rippling abs. On and on Pip’s orgasm went, spewing out quarts of cum—far more than Rumble had ever put out—until finally...

“Whew,” Pip finally said. He grinned down at the new five-foot-even Rumble and flexed a massive arm that filled the entirety of the smaller stallion’s vision. “That was fun.”

Rumble swallowed. His shirt had all but exploded around Pip’s size and physique; even the extra-large clothing looked to be too small to contain a stallion of that size. Pip was wondering at his new size, smirking at the way his muscular ass now nearly covered both couch cushions.

Pushing seven feet. It felt incredible. Rumble caught an eyeful of his own inch-and-a-half pecker and whimpered slightly.

Pip heard him. “Might want to cover that up,” he said, teasingly. “Not like me.” He set Rumble down on the couch beside him and stood up before striking a most muscular pose, every one of his muscles bulging out at once. He grinned down at his ruined shirt. “Well, I don’t think any of your clothing will even fit a stallion as big as me anymore. Might as well just go naked, huh, Rumble?”

“I don’t—” Rumble cut himself off, swallowing when he realized that his voice had come out as a much more higher-pitched, almost effeminate squeak. “I don’t think many ponies will approve, Pip.”

Pip just raised an eyebrow and bounced his pecs a few times. “And who’s going to stop me, hm? You?”

Rumble just shook his head. Pip loomed over him, larger than life. “No,” he said, that high-pitched voice slipping out again. “Not at all.”

Next Chapter: Chapter Four: Fill Her Up Estimated time remaining: 10 Minutes