Bulge

Twilight’s groan of pleasure was long, throaty, and thoroughly satisfied.

“Wow,” she said. She had one hoof on her overfilled, bulging belly and the other stretched out on the bed above her head. She held her tongue between her lips and sloshed her belly around a bit. “Just wow.”

Shining was still panting. The rush of orgasm had subsided to a dull roar in his ears, and for a moment, at least, he was able to seize control of his senses. Even with that, the ringing pleasure of his new equipment still threatened to bowl him over. He was happy enough to stay with his back against his pillows, his chest rising and falling steadily as he struggled to regain some amount of lucidity.

“How…” He swallowed, then reached out to run his hoof over one of his nuts. The oversized testicle throbbed in return. It was warm to the touch, and far too big for him to cover the entire thing with his hoof. A groan escaped his lips. He could actually feel it refilling with his seed, could feel it growing heavier by the second with new volumes of unspent cum. Though they had shrunk slightly after pumping so much of his load into Twilight, they were rapidly swelling again. He could even see the bed visibly depressing beneath their weight. He shuddered as a pulse of tentative pleasure swept through him.

Twilight grunted suddenly. Shining glanced over his package at her. At least now he could see the rest of her. His enormous shaft had gone at least slightly limp, and was now draped comfortably over his massive balls. His member had angled down over the top of his nuts, leaving his leg-thick head to brush against the bed. Meanwhile, Twilight was struggling to haul herself upright into a sitting position. Her overfull belly sloshed loudly, pinning her to the bed. A quick levitation spell helped her upright, and her cum-filled stomach flopped loudly into her lap.

“Whew,” Twilight panted. She shot him a wry smile. “Thank you.”

“Sure,” he said. He was still feeling more than a little bit winded, and even more lightheaded. Whether that was due to the incredible orgasm or the amount of blood now being redirected through his stallionhood, he wasn’t sure. He settled for both.

He shook his head. One of his hooves was still absently massaging his swollen, cum-laden orbs, while the other moved up to scratch at the back of his neck. “Well,” he said finally. “That was fun. Maybe we should think about shrinking this back down, though.” He gave Twilight’s stomach a pointed look.

Twilight’s jaw dropped. “You’re kidding, right?” She gritted her teeth, struggled to heft her body into a more comfortable position. “I thought you liked it!”

“I do!” he said. “It just seems a little bit unwieldy. I mean...look at these!” He waved a hoof over his groaning, churning orbs. “I just unloaded a ridiculous amount inside you, and they’re already filling up again! They look even bigger!”

Twilight licked her lips. “Well,” she said, looking contemplative, “that does mean you can go for a round two…”

Shining’s cock gave an appreciative throb at that. Shining grit his teeth as it began to stiffen again. Already, his head had lifted a good two inches off of the mattress, and his balls were feeling fuller than ever. “That’s not the point,” he said. “I can’t go to school like this. I can’t join the Royal Guard with...these! And if Mom and Dad see—”

“They don’t have to,” Twilight cut in. “I learned an invisibility spell last year, remember?”

Shining rubbed his forehead. “Yeah, but that doesn’t help if you’re not around.”

“And?” Suddenly, Twilight’s face held an expression of sly contemplation. “Just imagine it.”

“I’d rather not.”

“Come on,” she said, and pouted. “It’s so much fun, though.”

He sighed, then decided to humor it.

“Just imagine,” she said happily. “You’re walking through the hall, and everypony can see how big you are. Everypony can see your stallionhood bobbing beneath your chest, smacking against the insides of your legs—”

His real-life stallionhood was chubbing up even more. Without even thinking about it, Shining let one of his hooves drift down to a spot just below his medial ring. It massaged his shaft gently, working into the thick meat of his tool. It was already drooling pre, widening the already impressive lake of fluids gathered on the mattress.

“—with your big, full balls sloshing between your legs, so wide that you have to walk bowlegged, so full of musk that everypony in the entire building can smell your musk—”

He moaned under his breath as his cock lurched, shuddering with arousal. He could feel it swelling and hardening beneath his touch. He bit his lower lip and shivered as a thick glob of spooge spurted from his tip to join the growing puddle of his fluids. Twilight’s voice still filled his ears, her every word evincing another throb of his cock and, on every third word, another shuddering lurch and splatter of cum.

“—and everypony knowing that you’re that big, that you’re my big big brother, and that I’m the only mare who can even take half your girth—”

With a cry, Shining felt his whole stallionhood seize up. Now at full mast, it merely throbbed once before shooting a massive glob of spooge into the air. It splattered against the ceiling and stuck, save for a few thick ropes that were left hanging down toward them. Shining stared at his full erection, then blinked owlishly up at the mess it’d made above him.

“Huh.”

Twilight’s eyes glimmered predatorily. “So,” she said, almost innocently. “Would you still be against a second round?”

Fuck no.

He shook his head wildly. Twi grinned, fell back onto the bed. “Good. Then—”

But Shining had already shifted himself onto his knees, his massive erection bobbing in the air before him. He barely had to move at all before his member was poking against Twilight’s outer lips. Her mouth formed an “o” as he prodded against her labia—his shaft was easily as thick and nearly as long as one of her legs! And all that was going to go inside her?

But she didn’t even entertain those doubts for a second. “Well?” Twilight said. She raised an eyebrow. “What’re you waiting for, Shining? Your little sister’s ready for you.” She said the last bit in a high-pitched, sing-song voice that both irritated Shining and turned him on even more. He took a deep breath to regulate his throbbing heartbeat while his balls, feeling impossibly full, throbbed even harder. Then—not gently, but not painfully, either—he shoved his massive, flared head inside of her.

Twilight was on her back, so there wasn’t much for her to do but let her jaw hang open, her legs twitching helplessly as her brother spread her apart. “Ooh. Oh. Oh gods yes!” Her thighs, which she’d stretched out on either side, twitched and shook as Shining stretched her wider than she’d ever been stretched before. When she’d felt him stretching her muzzle, heard her jaw crack, she’d been almost afraid that he’d either snap her mouth in two or get stuck, given how big he was. But a mouth didn’t have an erogenous zone.

So instead, all Twilight felt now was pleasure: a rising tide of sensation that washed up her spine and crashed right over her chest. It mixed with tightness, pain—but a good pain, like stretching a muscle. And stretched she was. She felt a fire burning in her loins, both from arousal and tightness, as her big brother’s head alone stretched her wider than any toy she’d ever attempted before.

“Oh, gosh,” she heard him grunt. “Oh, gods. Twi, you’re so soft.”

“Stop...ngh...waiting,” Twilight panted, “and stick the rest of it in!” Another mare might have been terrified of Shining’s near two-foot tool, but not her. She wanted to be filled with it, wanted to be filled by it, wanted to make herself into a cocksleeve just waiting to become even fuller of her brother’s cum. She felt and heard her belly sloshing just above her as Shining reached forward, planted his hooves on her hips, and slowly eased the next few inches inside of her.

Six inches. Seven. Twilight’s eyes almost rolled up into her head as the feeling of fullness intensified. Oh, yes. “Keep going,” she panted. Her inner walls were quivering, quenching, leaking fluids around her brother’s shaft. She wanted more. She needed more.

And Shining was happy to provide. With a snort, he shoved another five inches inside of her. A jolt of electricity exploded up Twilight’s spine, fireworks going off on the back of her eyes, as she felt a full foot of her brother’s footlong pushing inside of her. He slid another few inches out of her, his balls rubbing against the mattress. She wanted to ask him why, wanted to make him stop, wanted to tell him that he was going the wrong way—and then he slammed his hips forward and rammed all twelve inches plus an additional four inside of her.

Sixteen inches. Oh, gods. His medial ring was inside of her. His medial ring was inside of her. How wide was it? Six inches? Seven? It didn’t matter. All that mattered was that her pussy was sucking in every inch of size her wonderful, incredible big brother had to offer, and that there was even more to come.

She groaned. A strand of saliva strung out between her lips. “Oh, gods,” she moaned. “Shining, you’re so big.”

He allowed himself a smirk. Sweat was beading on his forehead from the exertion of forcing his way inside of her alone. “Big enough?” he said, knowing her answer. She shook her head, then let out a cry of pleasure and pain as he slammed the last four inches inside of her. Fireworks. Lightning. An earthquake in her loins. She trembled, shook, cried out as she writhed around his shaft. Femcum streamed from her walls—and found itself stuck inside, with Shining’s massive tool providing an airtight seal between her marehood and the world outside. Oh, gods. Was that her womb?

She didn’t know. All she knew was that there were twenty inches of incredible, thick, stallion cock inside of her. There was only one thing to say.

“Fuck me,” she cried, and Shining did just that.

His hooves roamed hungrily over her rump, squeezing and rubbing her flanks as he drew back his hips and shoved back into her again and again. She groaned, twisted, moaned while his hips rocked back and forth. He couldn’t even pull all the way out—his stallionhood was just too huge—so he just pulled out to the length of his medial ring before plunging back inside of her. Twilight Sparkle just screamed and cried out in pleasure. She wanted this. She wanted him. She wanted all of this and more—faster, harder, deeper.

Shining’s massive balls, far too large to hang between his legs, instead just rocked back and forth in time with his thrusts. Their cum-filled depths sloshed and churned as Shining plowed his little sister, their oceans of seed swelling every time he hilted himself inside of her. Even though he’d just cum buckets, he was feeling incredibly, painfully pent-up. He needed to fill her up, needed to empty his cum-laden orbs inside of her. Shining felt his entire consciousness focused at the base of his shaft, and felt the pressure growing even more incredible with every thrust.

“More!” Twilight demanded. “More!” Her plush belly was wobbling from side to side, bouncing like jello with every thrust. Shining snorted, whinnied, tossed his mane as he squeezed her flanks even harder. Twilight could feel him pounding her womb, could feel him filling up every inch she had to give. But that wasn’t enough. “More!” she demanded, and her horn began to glow.

Shining didn’t realize what had happened at first. All he knew was that his pleasure had suddenly increase a hundredfold. He slammed his cock inside of her again and again, each time plunging even more of his size into her tight, dripping depths.

He was growing even larger. Twilight’s eyes rolled up into her head as Shining’s shaft hit—and passed—two feet in length. His balls swelled up, their spooge-filled contents sloshing and churning even more as they got big enough to actually start pushing his cock up and away from the mattress. Shining snorted, moaned, as his cock began to shudder and lurch with an insatiable need to cum inside of Twilight’s marehood.

It kept growing, passing twenty-eight inches without breaking a sweat. Twilight couldn’t breathe, couldn’t shout. She just stretched her mouth wide open in mindless ecstasy as orgasm after orgasm racked her body. Shining passed thirty inches, with a girth nearly as wide around as her waist. She caught it out of the corner of her eye—a massive, meaty bulge pushing out of her stomach, pushing past even the gallon or two of seed he’d filled her up earlier. Again and again he rammed into her, deforming her belly, plunging deep into her womb and stretching her very body around his cock like some kind of enormous condom. And Twilight just kept on screaming silently, her magic on a runaway mission as her body just kept lurching and writhing in absolute pleasure.

The scent of his own stallionhood was intoxicating. Shining groaned aloud as he struggled to keep his load down. He could feel it growing, swelling, sloshing in his enormous, cum-laden nuts. He needed release for those warm, heavy spheres. He needed to—

“Fuck me!” Twilight cried out, retrieving control over her vocal chords for a moment. He saw the massive bulge in her stomach, and for the first time realized what it was. “Fill me up. Breed me with your seed!”

Shining didn’t need to be told twice.

With a roar of impossible pleasure, he let the pressure in his loins go free. Instantly, the muscles of his hips tightened, flexed, jerked wildly as his thrusts lost all semblance of rhythm. He bottomed out in Twilight instantly, then groaned and snorted, panted and whinnied as copious amounts of ejaculate flooded straight into his little sister’s womb.

The cascade of cum crashed into Twilight’s insides, filling her up with a single spurt and going even past that by the second. Jets of spunk spattered audibly inside of Twilight’s womb as Shining’s massive, straining nuts released a torrent of cum inside of her. He fired shot after thick, gooey shot, her womb swelling up to join her belly and passing it in volume in a matter of seconds.

On and on he went, pumping out more and more spooge until Twilight’s belly had swollen up past the point of mere pregnancy. She looked about ready to bear twins—no, triplets—and still Shining’s jizz came. He slammed his shaft into her again and again as the spooge in his nuts churned and roiled. This was his release, his promise of love to his sister: this tidal wave of spooge, this erupting volcano of seed that would bloat her up until all of the world could see that she was his mare, until all of the world could see how much he loved his little sister.

He came for a good thirty seconds more, a veritable ocean of cum spilling out of his throbbing, lurching shaft and filling his sister up even more. Each rope of cum added another few cups of warm, creamy spooge to her swollen depths. Twilight’s grasp on sanity had long since left her, and she’d been reduced to moaning, shrieking in pleasure as her belly overflowed her grasp and actually fell past her sides until it touched the bed. She was full, so impossibly full. She needed this, needed it so badly. She wanted it to keep going, wanted it to never end—

Shining panted as he drained what felt like every last ounce of cum from his nuts. He let out a final cry as the last thick rope of spooge shot from his three-foot tool with the force of a rocket, then fell back onto the bed, all his energy spent.

The warm afterglow was already washing over him. Clouds began to drift across his mind. He closed his eyes as the last peak of pleasure rode him out and evaporated inside of him. Oh gods.

He was actually still inside of her—with a cock over three feet in length, just falling back onto the bed hadn’t done enough to dislodge his massive member from Twilight’s cunt. Twilight just moaned as her brother’s cock slowly went flaccid inside of her, reducing her stretch from insane to merely impossible. She wrapped both her hooves around her sloshing, cum-filled belly and wasn’t surprised in the last when she couldn’t reach even halfway around it.

“Fuck,” Shining said between pants. His tongue was hanging out of his mouth. His body shook with every breath. His hooves were trembling. “Oh fuck.”

“That,” Twilight breathed. “That was incredible.”

“Yeah.” Shining closed his eyes. Sweat was streaming down his forehead. “Oh, fuck. Thank you, Twily.”

She was more than a little bit indisposed in her current position. Her cum-bloated belly had to weigh as much as she did. Still, she was able to shift her legs, somewhat awkwardly, so that they were curled lovingly around Shining’s still throbbing tool. “Mm,” she murmured. “Thank you.”

He smiled drowsily at her over, or at least attempted to. His massive package and her enormous, sloshing belly kind of made eye contact a bit difficult. Still, it was nice to at least make the effort.

“We should do this again sometime,” he said.

“Yeah,” she said, sounding dreamy. “We definitely should.”

Suddenly, something slammed downstairs. “Kids!” Night Light’s voice sang out. “We’re home!”

Both Shining’s and Twilight’s eyes opened wide. “I thought you said we had two hours!” Shining hissed at her. He needed to try and get up, try to leave the room, but his package was so heavy, and he felt so warm, so slow…

“I...ngh...did!” Twilight grunted, struggling—and failing—to budge beneath her ponderous, cum-filled bulk. “They told me nine!”

“The restaurant was closed!” Twilight Velvet’s voice floated down the hallway. “So we decided to come home and have a nice family dinner together.”

“Fuck, fuck, fuck,” Shining was chanting. They had to hide, had to escape, had to stop this, somehow. He managed to swing his body around the side of the bed—pulling his massive member out of Twilight’s pussy with a loud-sounding schlick and letting a few pints of his seed cascade free—but tripped over his own enormous balls, landing straight on his face. The floor thumped.

“Everything okay?” They could hear hoofsteps approaching the room. Twilight Velvet sounded concerned. “Shiny, are you in there?” The unmistakeable sound of a hoof on the doorknob reached their ears.

Shining and Twilight thought the exact same word.

Shit.