Please

For a few moments, the two of them lay there: Shining, his head sinking back into a pillow, and Twilight, snuggled against his chest. For a minute, Shining heard only Twilight’s soft breaths, felt only the rise and fall of her chest against his own.

Then, Twilight looked up at him. “Shining?” she asked.

“Mmhm?”

“Was that...sex?”

Shining hesitated. “Kind of,” he said. “When you were sucking on my...well, penis, that was what’s called ‘oral sex’.” He coughed. “Though that’s not entirely what sex usually refers to, no.”

Twilight’s nose wrinkled. “But you felt good, and I felt good,” she said. “If that’s not sex, then what is sex?”

Shining’s hoof brushed against her fillyhood, and Twilight moaned cutely. “Well,” he murmured, nuzzling her cheek. “It’s when a stallion puts his cock inside of a mare’s private parts.”

“My vagina?” Twilight asked. Shining nodded. “Can we...do that?”

Instantly, Shining’s cock throbbed. His nostrils flared, and a wave of arousal hit him. Struggling to keep his sudden lust under control, he shot his sister a strained smile. “Are you sure? It might...hurt, a little.”

“Would you have sex with Cadance?”

“I—geeze, Twilight.” Shining scratched the back of his neck, chuckling awkwardly. “If she’d let me, sure. Though don’t tell her that,” he added quickly.

“Then why not me?” Twilight cuddled into Shining’s chest. “Don’t you love me more?”

“Uh…” Shining swallowed. His re-emerging arousal was rapidly lapping up against the sides of his mind. Not only was he still somewhat pent-up, but Twilight was willing… He’d longed for days to pound that prime filly ass, and now she was just offering it to him?

He swallowed again. “I love both of you,” he said quickly. Then he winced, his cock giving a particularly violent throb. A fat glob of pre splattered onto Twilight’s back, breaking over her fur with rivulets of warm, milky-white.

Welp. That made up his mind for him. Somewhat sheepishly, Shining said, “Heh. Guess I’m still pretty turned on.” He shrugged his shoulders and grunted. “So, if you really want to…”

“I do!” Twilight nodded firmly. “I want to know everything about sex.”

“Everything might be a bit of a tall order,” he said dryly. “But we can start here.” He checked the door again—still closed—and threw up a quick shield spell to be sure. It would filter out most of the noise; frankly, if things got loud, he wanted to make sure that nopony heard them at all.

Twilight turned over and lay her belly on his chest.  She pushed herself forward; as her chest pushed against his, her tight little flank pushed up a few inches into the air. Shining could barely keep his eyes off it. “So what do we do?” she asked. Shining half expected her to take out a notebook and quill.

“We do this,” Shining said, and kissed her again.

Nopony in their right mind would expect a filly to be a good kisser. All the same, there was an...innocence to Twilight’s lips that pushed Shining onward, a curiosity that drove her into new experiences. She didn’t quite understand what Shining’s tongue was doing in her mouth—that much was clear. But she reciprocated nonetheless, clearly doing her best to investigate this strange new act. Shining moaned into the kiss as her little hoof traced down his chest, his cock throbbing against her flank.

His flare was aligned with her fillyhood; he could feel her slit brushing against his tip, her warm folds teasing him with their slickness. Shining pushed his shaft right up against her opening and heard Twilight gasp. He let her pull away from the kiss, her eyes wide.

“Is that—is that you?” she asked him.

Shining nodded. “I’m going to put it inside of you, okay?” Twilight’s muzzle shook slightly, but she nodded. Taking that as a green light, Shining returned his focus to Twilight’s flank.

Tenderly, he spread her flanks so that his member would have ample room to move in. Each one of her cute little butt cheeks was barely bigger than his flare; in fact, his entire cock just dominated his view of her backside. As one edge of his flare slipped inside of her, Twilight gasped again. She’d bit down on her lip, her eyes wide as she felt him push his way inside of her.

“Is that alright?”

Twilight’s head bobbed. Shining decided to keep going.

He pushed a bit further in—and Twilight groaned. Shining almost did, too. She was so tight. He felt like he could barely get even half of his mast inside of her—and that was just by girth. Her tight fillyhood had clearly never been penetrated before tonight, and just one edge of Shining’s fat cock was already stretching her to a breaking point.

Twilight whimpered softly as Shining pushed himself further inside of her. “I-it’s so big,” she panted. “Ooh. Oh, oh.”

“Does it hurt? Should I stop?”

Twilight shook her head. “I wanna finish,” she said firmly. Shining sighed good-naturedly, but a throb of his cock reminded him of his priorities. Gritting his teeth, he spread Twilight’s flanks a little wider and pushed.

She cried out, unable to stifle her gasp of pain as his entire flare pushed into her nethers. Instantly, Shining felt an incredible tightness, like nothing he’d ever known. He felt like he could barely move an inch forward or back; when he flexed his shaft on reflex, Twilight’s inner walls bulged around him, molding to the shape of his cock.

And he was only an inch and a half inside of her.

Putting on his best big-brother face, Shining reached up and brushed a strand of her mane out of her eyes. “It’s okay,” he hushed. “It’s in. That’s the widest part. It’s in.”

Twilight hiccuped. “It...is?” she asked uncertainly. His cock throbbed inside of her, and she squirmed a bit. “O-ooh. I can f-feel it.”

“How does it feel?” he asked her.

She grunted, one eye squinting. “Like...like you’re just there,” she mumbled. “In all of me. I don’t know.”

“Don’t worry too much about it,” Shining said. He smirked at her. “Just...try to enjoy it, okay?” She smiled back.

Slowly, Shining eased himself into her. Twilight moaned, squirming as he embedded more of his shaft inside of her. Inch by thick, meaty inch of his turgid stallionhood filled up her fillyhood. He could feel her stretching around him, her tiny filly body flexing around his shaft as he pushed her body into new shapes with every inch. Her flanks clenched around his shaft, stroking his length as he pushed himself even further inside of her.

By the time she’d pushed down to his medial ring, Shining had buried a full eight inches of his length in his sister’s cunt. Twilight groaned, mewling softly as each new inch of her big brother’s meat was hilted in her virgin pussy. Finally, after hiccuping again, she grunted and said, “I-I don’t think it will go in any more.” She bared her teeth in something resembled a smile, droplets of sweat beading on her forehead.

Only about half of Shining’s cock was buried inside of her. As he shifted her on his chest, though, he felt something wide and hard pushing against his chest. His eyes widening, he pushed Twilight a bit off of his stomach, keeping his cock firmly inside of her.

A fat, round bulge strained against Twilight’s stomach, the flare of Shining’s member clearly visible against the outline of her skin. Twilight groaned as he twitched inside of her, the circle of his head shifting against her walls and stretching her in new ways.

“O-ooh,” Twilight moaned. Shining took hold of one of her hooves and held it over the bulge in her tummy.

“You feel that?” he asked. “That’s me, inside of you.” He gave his hips a little jerk, and another half-inch of his length pumped past Twilight’s winking lips. Her lips opened into a wordless whimper, something in between pleasure and pain swirling in her eyes.

Twilight swallowed. Her hoof rubbed against the bulge in her stomach. She traced across every contour, every curve of his flare. His cock lurched inside of her; he could feel the splatter of precum against her warm, tight insides. Twilight’s answering moan matched the tightening of her fillyhood around his girth.

“How do you feel?” Shining asked.

Twilight licked her lips. “...Full,” she said, after a moment. She had her hooves on his stomach, and was just barely able to keep herself from going any lower by balancing on either one of his thighs.

Shining grinned up at her. He curled his hooves tighter around her waist. He could feel the curve of her hips beneath them. For now, they were tight, slender, smooth—but one day, they’d be a mare’s hips. His erection twitched, and for a moment, he couldn’t decide which one he preferred. If he were honest with himself, though, he didn’t really care.

Both were Twilight, after all.

He rubbed the mound on her tummy softly, savoring the sensation of being inside of her. “You feel full, huh?” he murmured, stroking her fur. “That’s just how much I love you.”

“Love you too,” Twilight mumbled. She slipped another half-inch down Shining’s cock, spearing herself further. A moan burst from her lips, a thin string of saliva going from the top of her bottom to the top. She was panting slightly, still over-stretched from Shining’s girth inside of her. “O-ooh.”

Shining darted up and planted a kiss on her lips. When he came back down, his hips pushed up. The very edge of his medial ring brushed against Twilight’s filly lips, driving her eyes wide open. As another glob of his precum burst against her walls, he pulled his hips back down. His flanks sank a bit into the quilt before pushing back up again. Before long, he was pumping his length into Twilight like a piston, slowly at first, then faster, harder, the sounds of her labia schlicking down his member mixing with her steady pants and moans.

Shining’s mind was a mess of pleasure, satisfaction, shame, and pride. He’d done more than introduce Twilight to sex. He was taking his sister’s virginity—his filly sister, who’d be barely old enough to even do math if she weren’t a damned genius.

And he loved it. Oh, but he loved it. Biting his lip, Shining grunted out. “Oh, f-fuck, Twilight. You’re just so tight.”

Twilight squeaked. His medial ring had shoved up against her fillyhood again, pushing her marehood to its limits. “Y-you’re so big,” she retorted.

Her words just made Shining’s erection throb even harder. His balls were churning between his legs, sloshing every time he bounced Twilight up on his cock. He fucked her like a pogo stick, bouncing her up and down, rocking his hips up and down as he pistoned himself inside of her again and again. Pre was leaking from her lips, which were clamped tightly around his member. It streamed down his shaft in milky white rivulets. He could feel his nuts swelling with cum, filling up as they prepared to unleash their load right into—

• his sister.

Shining groaned. He rubbed the base of Twilight’s flanks, savoring the softness of her Cutie Marks. When she went all the way down, now, she made it almost two-thirds of the way down his cock. Given that his shaft was more than half as long as her torso, that itself was an impressive feat. The snugness of Twilight’s insides, forbidden to him for so long, embraced his flaring girth with a velvety caress that threatened to squeeze and milk him dry.

Every pump of his hips made his cock spasm in Twilight’s cunt. Before long, a good three inches of his length was straining against her belly every time he thrust himself inside of her. The sheer amount of precum pouring into her, the ocean formed by Shining’s pent-up weekend, was starting to round out her tummy, too; he could hear her womb starting to slosh in symphony with the half-gallon of spunk he’d unloaded into her stomach.

“Twilight,” Shining grunted. “If—if we keep going, I’m—I’m going to cum again.”

Twilight’s reply trembled a bit. “Am—am I going to cum too?”

Shining’s muzzle curled into a smile. Sweat rolled down his cheeks from the effort of fucking his sister. “You will,” he grunted, shoving his hips up into the air. A squealing moan burst from Twilight’s lips as his shaft bulged obscenely from her belly, spreading her cute filly flanks wide around his slick ring. Inside or outside—it was no longer a question. He gave her flanks a squeeze, and grinned when she squealed again. He was going to fuck Twilight’s pussy wide, and was going to pump her ripe, prime fillyhood with cum. He, Shining Armor, B.B.B.F.F., was going to be the first stallion to ever jizz inside of his little sister’s fillyhood—and he was going to fill her with his seed until she was ready to burst. The reality of his fantasies was finally hitting him; his libido was roaring in his ears, demanding a release. “And it will feel amazing, I promise.”

“Sh-shining,” Twilight mumbled. Her hooves was shaking. “O-oh, Shining, this feels so good. I—I—oh!”

The pressure in Shining’s loins reached a tipping point. On reflex alone, he yanked Twilight all the way down to his crotch. He bottomed out inside of her, her little filly’s haunches folding over his fat, churning nuts as her cunt contracted and spasmed. Twilight’s squeals of pleasure filled his ears, the absolutely massive bulge of the cock spearing his sister’s fillyhood filling Shining’s eyes completely.

As Twilight squealed, her legs and arms spasming and her pussy walls contracting, Shining felt himself go over the edge. He came—and he came hard.

Grunting with absolute pleasure, it was a struggle for Shining to keep his lucidity as he came inside of Twilight. His cock flared hugely, flooding Twilight’s fillyhood with his cum. He could hear it splattering against her insides, could feel her warm walls squeezing around his cock and milking him dry. He imagined her begging him for more, begging to be filled up with his jizz.

And fill her up he did. Shining groaned, again and again. His hips jerked wildly, thrusting up and deforming Twilight’s stomach around his flare repeatedly. He could actually see the smaller bulge atop his tip, where the steady flood of his hot jism into her young, virginal womb was pushing against her skin and filling her up. His cock lurched and contracted, shot after shot of his load erupting inside of his little sister as he filled her up with his load.

Before long, Twilight was groaning, her little hooves straining to reach around her distended belly. Sweat poured down Shining’s forehead; his hooves were slick with it, coated in a mix of his and Twilight’s juices, their musks—his, masculine and sexual, hers innocent and sweet—filling the air of the room as both filly and colt sang out through their climaxes.

After what felt like an eternity, Shining’s orgasm finally stopped. Twilight’s own legs had finally stopped their violent spasms, and had now settled to just twitch against his sides with the aftershocks of her peak. Panting, Shining let the warmth of release spread through his system, the empowering embrace of satisfaction falling over his mind. With a grunt, he turned over onto his side; his cock slipped out of Twilight’s fillyhood and slapped against his belly. His sister hit the mattress with a thump and groaned, still cradling her swollen stomach in her hooves. He could hear it sloshing with his seed, and felt a perverse, glowing sort of pride in his chest. She’d been able to take it all—had been able to take all of him.

Panting, Shining reached over and turned Twilight to face him. She was panting too, and looked even more exhausted than he did. And yet, there was a glow about her, a shimmer behind those tired eyes that betrayed a happiness and satisfaction far beyond what he’d even dare hope for.

“How was that?” he murmured. He reached up to stroke her mane. “Feel like you learned enough about sex?”

Twilight groaned, though her muzzle turned upward into a smile. “I learned a lot,” she giggled, hefting her oversized belly.

Shining’s cheeks flushed. “That...doesn’t usually happen,” he confessed. “I don’t think. I was just...really pent-up.”

Twilight’s face reddened, too. “I really like having a belly this big,” she said. “It’s so round and soft. And...I can feel you inside me, even though you’re not.”

Shining’s blush intensified. So what if this was wrong? It felt...right. Lying here with Twilight like this. On an impulse he could register as neither solely brotherly, nor sexual, he curled a hoof around Twilight’s shoulder and hugged her close to his chest. Perhaps it was both.

“Do you like feeling me inside you?” he whispered.

Twilight nodded shyly. “...Yes,” she said. She nuzzled against his chest. Shining felt a tingle go up his spine.

He swallowed. He knew what he wanted to say next. But he didn’t know if he could. Tonight had been fueled—brought about, really, by desperation. By a strange, twisted obsession born of an all-empowering, entirely physical need. And yet...feeling Twilight curled up beside him, feeling her heartbeat against his chest, the soft stirring of her dripping nethers against his hoof… The pure rightness of it all washed over him, and suddenly he knew what to say.

“Would you...want to do it again sometime, maybe?” he said quietly.

Twilight yawned. “Mmhm.”

“Okay,” he said. “But you can’t tell Mom and Dad, okay?”

Twilight blinked blearily up at him. “Why not?” she said.

Shining tried to shove down an awry pang of guilt. “Because they’d...get mad,” he said. “Just like the Talk, okay? It’ll just be between us.”

Twilight appeared to think about that for a minute. Finally, she bobbed her head pleasantly and buried her muzzle in Shining’s side again. “‘Kay,” he heard her say, muffled and sleepy.

He sighed, grinning helplessly. Well. That was that.

Shining glanced back toward the door. He’d have to leave soon, and hope that neither Mom nor Dad had checked in on his room in the meantime. But…

He could cuddle with Twilight. He could share in her first afterglow, if only for a little while longer.

He loved her, after all. She could expect nothing less.