Bulge

Knock knock.

Shining Armor didn’t even look up from his comic. “Come in!”

His door creaked open. Shining’s ears twitched at the sound of a familiar, “Hello…”

He glanced up over his current page. Instantly, there was a red tinge on his cheeks. Twilight stood in the doorway, appearing, to all the world, to be the angelic little sister that the whole family knew her to be. Yet one detail was off—her eyes, usually bright and innocent, were half-lidded, perfectly framing the sly smirk that had crept its way onto her face.

“Oh!” Shining scrambled to set his comic aside. It slid onto his night-table, forgotten. “Twily! Right!” Oh, who was he kidding; he’d known she’d be coming.

She laughed. “Good to see you too, BBBFF.” She trotted into his room and swung the door shut behind her. Shining could barely keep his eyes off of her swaying hips, her round, curved flank—

He snapped himself back to reality. Twilight was looking at one of his posters, the Sky-High Fliers one. “That one new?”

“Uh,” he said. “Don’t think so.”

“Huh,” she said. She turned to him. She was smiling from ear to ear. There was something almost...unnerving about that smile. A wiser stallion might have paused.

But to hay with that. Shining grinned awkwardly back. “Mom and Dad?”

“Out to dinner.” Twilight checked the clock above his bed. “Won’t be back for a good...two hours.”

Shining’s whole body relaxed. He slowly exhaled, releasing a breath he hadn’t known he’d been holding. “Good,” he said. He was almost surprised when he realized that he meant it. Could he really have been looking forward to this this much?

He looked up and met Twilight’s eyes. They glittered in response, mischief darting about in deep-violet irises. Damn him, but he had. He licked his lips again, swallowed.

“Good,” he said again.

Twilight hopped onto the bed beside him. She grinned, laid a hoof the inside of his back leg. “You even dressed up for me!” Her voice squeaked, for an instant sounding like the adorable little sister he’d always had. Then he saw where her gaze was pointed, and his heart sank—but something else rose.

“Uh,” he said again. He blushed even harder. “Yeah. I guess I did.”

Twilight bit her lip, met his eyes. “Can I…?” He nodded.

She giggled to herself as her hoof made gentle strokes down his thighs, slowly but surely getting closer to the space in between. Her hoof brushed against his crotch and he gasped.

Twilight giggled again. “You’re excited, Shiny.”

Shining grinned, helplessly. “That obvious, huh?”

Twilight nuzzled her brother’s crotch. “Mm. I really love the smell.”

Shining bit his lip. His hooves dug into the bed and clenched the sheets tight. Suddenly, he was getting second thoughts. “Ungh. Twilight? You sure...we should...ungh.”

She ignored him, of course. The funny thing was, he wasn’t even nude. Of course, ponies were usually nude anyway, but he’d snagged a pair of briefs earlier in the evening. Whether they were there to conceal or to emphasize, though, was up for grabs. Since he’d known Twilight would be coming that night, it wasn’t difficult to guess which.

Her muzzle prodded again at his groin. Shining groaned as her mane brushed against his thighs. Another stallion, perhaps, would have succeeded in hiding his package beneath the clean white fabric. But for a stallion of his size, the exact opposite was true.

With a shaft that was seven inches long soft, and a pair of balls each three inches across, the pair of briefs did little more than accentuate his already impressive size. His balls bulged impressively against the fabric, while his flaccid dick curled up into a thick bulge of its own a bit further up his crotch.

Shining moaned softly as Twilight nuzzled deeper into his crotch. His own musk reached him, causing his nostrils to flare. It was a rich, deep scent, and he felt his dick twitch at the smell.

Then he imagined their parents coming back home early. Surprising them. Catching them in the act. The shouting, the anger, the punishments—

“Not tonight, Twily,” he muttered. He made a halfhearted attempt to push her off. “I’m tired.”

Predictably, she didn’t listen. “You know,” she said, laying her head across his thigh. “I was thinking about you today.” Oh, boy. “And then I came in here and found you all dressed up for me.”

“It wasn’t—” he began. The words melted from his mouth as she slowly drew her tongue across the inside of his thigh, her eyes half-lidded.

Twilight giggled. “See,” she said, her hoof tracing small circles over his package, “I really like seeing you in these. Makes me realize just how big you are.” She shuddered happily; Shining could swear that he saw her thighs clench as she tasted the word. “Makes me realize how lucky I am to have you for a BBBFF.

“But,” she said. She gave one of his fat, bulging orbs a gentle squeeze. He gasped lightly, his lips forming the shape of an “o”. His dick just twitched again, this time even harder. “That just made me think about how much better you’d look bigger.”

“Uh.” Shining swallowed. He could feel his dick getting harder already. He was suddenly extremely aware of the seed weighing down his balls, and of the tightness of the briefs around his crotch. His dick gave another twitch. Glancing down, he could see it already poking up against the left leg-hole of his underwear, its thick head an obvious, even obscene bulge against the fabric.

His right leg twitched. Biting his lip, he noticed that there was a damp spot spreading across his underwear. He glanced back up and met Twily’s eyes. What he saw there did not encourage him.

“Twi,” he said. The tip of her horn was flickering purple. “What—nggh—are you doing?”

Her smile was absolutely angelic. “Making sure my Big Brother Best Fuckbuddy Forever stays big,” she said. With that, she planted a kiss on the top of his bulging briefs—and released the spell.

Shining groaned as the magic went to work. He could feel it in his loins: a warm, tugging feeling that filled his entire crotch. “Twily,” he said. He was about to say ‘no,’ but an overpowering sensation of tightness soon overwhelmed him.

Out of the corner of his eye, he could see the bulge in his briefs swelling, growing larger and larger by the second. His eyes widened slightly. His cock was now fully erect: eleven inches of thick stallion meat, straining against the fabric of his underwear as hard as it could. The damp spot just kept growing, easily doubling in area as the steady flow of pre from his tip only increased.

But as he watched, shock evident in his eyes, his boner got even bigger. He watched it swell, thickening until it was nearly half as wide as his hoof. On and on it grew, passing a foot in length—no, fourteen inches, now—until it was clear that the underwear could take no more.

With a rush of cool air and an overpowering sense of relief, Shining’s cock pushed free of its tight, musky prison and slid down his leg like a long, hard snake. Sixteen inches. Seventeen. It finally tapered off at an incredible nineteen inches, a shaft so huge that most stallions could only dream of its length.

He winced and let out a grunt. Another glance at his crotch gave him the answer why. His balls had swelled up to the size of oranges, and were straining against the briefs even more powerfully than his shaft had. He grit his teeth as they grew into veritable melons, their six-inch diameters bulging obscenely between his legs.

The underwear was so tight. His breath came in short, tight spurts as he struggled to keep himself together. He began to sweat. He could feel the cum sloshing in their depths, could feel those lakes of seed filling and swelling by the second. By now, the fabric had been stretched so thin that it just clung to his enormous package, every square inch of area outlined by a clean, glaring white.

And the weight. They were so heavy. So...big.

He met his sister’s eyes. Her smile spread ear to ear. He smiled back.

She laid a casual hoof on his bulge. Shining’s whole body stiffened, and his cock flared, spurting out a few thick ropes of cum without any further stimulation.

“So,” his little sister said, that angelic look on her face again. “Do you like it?”