Cadance grinned a sly little grin over her shoulder at Shining Armor as the two of them walked from the Ponyville train station toward Twilight's castle, where they had been invited to stay for the weekend.

Thankfully, there had been no royal fanfare at the station... But Shining knew that little smile on Cadance's face, and it usually meant he was in some kind of trouble. Then again, from the way she was dressed – she was wearing one of her more provocative royal gowns, one that fit her body tightly, with a long slit up the side of her leg to her cutie mark and a deep cut of cleavage – maybe the trouble he was in would end up being some kind of sexy trouble... That was always the best kind of trouble to be in.

Well, better to face it head-on, no matter which kind of trouble it was. “Honey,” he asked very carefully, “is anything wrong?”

“Not wrong, no.” She looked back at him ... with even more of a smirk this time. “Isn't it interesting, though, that we'd come to visit Ponyville on this particular weekend?”

He hurried a bit and came up beside her ... instead of staring at the sumptuous curves of her ass through her white and gold dress, as he had been. “Oh, is there something special this weekend?” Playing dumb and innocent had always been a pretty good strategy in the past...

“Anything special? Hm...” Cadance tapped her chin with one finger, putting a playful sway into her hips as she walked. “Well, there is Sharing Day tomorrow.”

“Sharing Day?” Shining shrugged.

Cadance shot him a cold glare for just a moment. Maybe he'd been playing it a little too dumb and innocent... Her wry smile soon returned, though. She edged a little closer to him, twirling a finger through the short fur of his cheek. “You know, the day every year when – by my own decree – everypony has to share their romantic partners, with no guilt and no repercussions?”

“Oh, right.” He nodded as if he'd just remembered. “That was part of that act you passed like five years ago, right? The one that was supposed to fix Equestria's slow reproduction rate?” He shrugged again. “I hadn't realized that was tomorrow.”

“Isn't it interesting that we're going to visit your sister's castle during this weekend, then? Hm... why might that be?” Cadance looked at him, raising an eyebrow.

“Well, she invited us over.”

“And why do you think she chose this weekend to invite us?” Her eyebrow rose even more, and her suggestive little grin returned.

“It probably slipped her mind, just like me. I'm sure she just wants to see one of her oldest friends and her big brother. She probably didn't even realize what day it was.”

“Right. Because if there's one thing our little Twilight is famous for, it's completely losing track of things like what day it is.” She gave him a playful jab in the ribs. “Come on, you can tell me. No repercussions, remember?”

“Oh, look!” he said, glad for any excuse to change the subject. “We're almost there! And just look what she's done with the place... We have to ask her who made those banners hanging from the balconies. Don't you think something like those would look amazing on the Crystal Palace? But maybe in blue, instead of purple.”

Cadance shook her head slowly and rolled her eyes at him. “I'm sure it was Rarity who made those banners.” Taking his hand in hers, she led him toward Twilight's castle. “Well, come on. I suppose I can't make you talk about your plans for tomorrow if you don't want to. But I want to spend a little time with Twilight before you two are so busy fucking each other's brains out that neither of you have any time for me.”

Shining's eyes went wide. Sure, it shouldn't have been that hard to deduce, but to hear it said out loud, so blatantly ... by his wife... He gulped, but he still knocked on Twilight's door when Cadance led him up to it. Even if Cadance had figured it out, she had no right to complain. Tomorrow was Sharing Day, after all.

* * *

The next morning, Shining woke up late -- to an empty, lonely guest bedroom. Cadance wasn't in their suite's sitting room, or the small kitchen, or even in the bathroom. And she'd taken her purse... She must have gotten an early start. For the first time, it occurred to him to wonder what she was getting up to on Sharing Day.

He shrugged it off, though. Whatever she was doing today, it was her right. And he had his own plans to prepare for.

After a quick freshening up in the bathroom – where he noticed evidence of Cadance's unusually extensive early-morning makeup and beauty routine – he wandered out into the main hall of Twilight's castle.

There was a lavender-colored rose petal on the floor in front of the entrance to his suite. He picked it up... It carried the scent of a familiar perfume – a scent that triggered some very provocative memories of Sharing Days in the past. There was another rose petal in view, halfway down the hall, in the direction of Twilight's rooms.

He smiled, feeling the heat in his cheeks. For such a book nerd, she could be quite the romantic sometimes...

The very last rose petal was right in front of the door to Twilight's bedroom. Shining had a hand stuffed full of them by now – it wouldn't do for somepony else to follow the trail and interrupt them, now would it?

He knocked. Even though he knew he'd be welcome, it was only polite.

“Is that you, Shining?” The sound of her voice made his cock bulge inside his pants.

“Uh-huh.”

“Come inside...”

The tone of voice she'd said that in made him gasp. His hand trembled as he fumbled for the doorknob.

What he saw inside made his other hand lose its grip. The bundle of lavender rose petals fluttered down onto the floor.

Twilight was kneeling on the floor in front of him, stark naked except for a black blindfold and a matching bolt of silk tying her arms together behind her back. A tiny puddle of her juices pooled on the floor between her knees. How long had she been waiting like this?

The moment he closed the door behind him, she leaned forward and tilted her head back a little, opening her mouth wide and sticking out her tongue.

Such a romantic...

Shining fumbled for the button on his pants. It seemed to take ages to get them off. And all the while, Twilight knelt there, her tongue patiently waiting for a certain item to be placed onto it.

Finally he managed to yank his pants down – and his boxers with them. His cock sprung free, almost fully erect already. It wobbled back and forth between him and Twilight, almost bopping her on the nose at one point before he managed to kick his pants off of his feet.

He grabbed it and guided it exactly where it needed to go. The moment the broad, flat tip of it settled against Twilight's pink tongue, she moaned deeply, lunging forward until she'd taken him nearly all the way to his medial ring. He let loose a deep grunt of satisfaction himself as he felt the tip of his cock slide effortlessly into his little sister's throat.

“F-fuck, Twilight...” He gasped and stroked her mane as she bobbed her head up and down. “Where'd you learn how to do that?”

“Mmm-mm mmm...” Apparently, Twilight wasn't going to take a break for long enough to dignify that with an answer. Instead, she willfully shoved herself down even further. His medial ring disappeared between her lips, and despite the blindfold, he could tell that she was looking up toward him adoringly.

But she was getting a little too ambitious. Her throat constricted, and she made little glugging, choking noises. Thick streams of her spit leaked out from her mouth around his shaft and plopped down onto the floor between them. The corners of the blindfold began to darken with dampness ... tears, no doubt.

“Twiley,” he said. “You don't have to— Oh! Oh Goddess!”

She'd shoved herself down all the way. Her drool now collected around the rim of his sheath, dripping down onto his balls. She jerked back and forth, no longer able to control her gagging ... could she even pull herself up if she wanted to, with her arms tied behind her like that?

As incredible as sinking deep inside her throat felt, Shining didn't want to be the death of his sister. He grabbed her horn – the moment he did, she moaned around his shaft in satisfaction – and he forcibly pulled her back up until only his tip remained inside.

She sucked in deep, greedy breaths through her nose, even as she strained against his grip on her horn, trying to push herself down again.

Shining let her ... but only a little. He had to hold his sister back the whole time, or she'd deep-throat him until she passed out. It was a strange inversion of the kind of encouragement most mares needed ... but then again, that sort of thing was why he loved his sister so much. Too bad Sharing Day was only one day a year!

Taking advantage of every opportunity Shining's rhythm gave her, Twilight swallowed his cock like she was desperate for it. Whenever he held her back, she slathered her tongue over as much of his shaft as she could reach, moaning as if begging to be let loose again.

Even with the distraction of holding her back, Shining felt himself getting close ... and now was far too soon. Twilight could teach even Cadance – The Princess of Love – a thing or two about blowjobs. But as good as her mouth felt, and as satisfying as it would be to let her go as deep as she wanted and pump his load straight down her throat, he wanted more from today than just a blowjob. Much more.

He pulled Twilight up ... all the way up. Her tongue stretched out, licking his flattened tip as he held her back, struggling for that last little bit of contact. The moment he released her, she dove back down again. He'd pulled his cock out of the way, so she didn't manage to deep-throat him again, but she didn't miss a beat. She slid her cheek against his spit-slick shaft, following it down until she found his balls, where she nuzzled in close, breathing deep from his musk and luxuriantly licking the smooth-curved skin.

“Oh Twiley,” he said, staring at her down there. The sight of her blindfolded, his dampened cock pressed against her mane as she worshiped his balls with her muzzle... He shook his head. No. If he was going to give his sister the treatment she deserved, he would have to do it forcefully ... and if the way she'd tied herself up was any indication, a little forcefulness was exactly what she wanted from him.

So he reached down, grabbed her by the shoulders, and hauled her up. She was surprisingly light, despite how much she'd grown since they were kids. Carrying her over his shoulder – with a hand conveniently placed on her shapely purple ass – he hauled her over to her own bed and tossed her down on it.

Twilight squealed and landed on her back, softening the blow against her tied hands with just the briefest flash of magic. Good – that meant she was still giving some thought to self-preservation.

Before she could jump up and lunge for his cock again, Shining held her down with a firm palm pressed against her slim belly, on the firm curve just below her belly button.

She must have figured out what he had in mind, because she moaned and spread her legs open wider.

Shining grinned as he saw her purple pussy lips open slightly, showing him a slit of pink inside. And Goddess ... he'd never seen her so absolutely sopping wet before. Little clear rivulets matted the fur on each of her thighs, and her entrance was still dripping, even as he looked at her.

Still, even as turned-on as his sister obviously was, it wouldn't hurt to tease her a little...

He began by tasting the drips along her thighs. Her legs twitched as his tongue touched them, tickling her sensitive spots around her inner thighs – spots he'd known about since before either one of them was old enough to know why it wasn't appropriate for a brother to touch a sister there...

From the neediness of her moans, though, he knew there was only so much teasing she was prepared to take before she'd drop her submissive act and just use her magic to shove his muzzle where she wanted it.

Of course, she didn't need to do that. Shining wanted to be the best brother he could be, so he gave her what she wanted without making her take it from him. He skipped the rest of the teasing and went straight for the juicy pink slit that needed attention so badly.

Twilight gasped when he first licked her from bottom to top. Her whole body jerked when his tongue slid over her clit.

Shining grinned to himself – despite lips coated with his own sister's unmentionable fluids. He had her exactly where he wanted her ... and it wouldn't be long now. He gave her exactly what he knew set her off so well: slow, rolling licks back and forth up between her lips, then gently suckling on her clit while teasing it with the tip of his tongue – and just as it started to get too intense, he'd start over with the rolling lick again, building her up to an even higher peak.

“Shining, Shining,” Twilight panted. “Oh Shining!”

He kept going. He knew she wasn't truly close to the edge until he heard...

“Unh! B-B-B-F-fffuck!” Her whole body tensed, her legs trembling against his shoulders.

Shining stopped teasing her clit and instead stuck his tongue into her entrance – far deeper than he had before – to feel her pussy pulsing around his tongue, and to taste the love-juices that spurted into his mouth. He hummed a satisfied moan into her pussy lips, taking satisfaction in a job – and a sister – well-done.

It wasn't over, though, when – grinning lips dripping -- he stood up above her still-shaking body. Stroking his cock a little, he got down into position at the side of the bed, lining himself up.

Goddess, she was cute! His wife might be beautiful, one of the most gorgeous mares in all of Equestria, even ... but Twilight was just so damn adorable. Her purple breasts were perky enough, but not the voluptuous melons his wife sported. And instead of his wife's carefully-toned abs, Twilight had a little bit of a soft belly to her – just enough belly to accentuate her curves and make the way it narrowed down to her puffy little pussy lips between her thighs all the more irresistible.

Shining grabbed her hips – a little bit narrower than Cadance's well-developed ones -- with both hands, lining the tip of his cock up with his sister's wet and ready pussy.

“Yes!” she gasped as she felt his tip there. “Please tell me you're not going to use a---”

Shining pressed forward a little. His sister's pussy lips gradually spread open, and then in a sudden pop, the broad tip of his cock slid inside her.

“Mmm...” Twilight squirmed back and forth on top of her bed, working her pussy a little farther down his cock as she moved. “Yes... You didn't use a condom. I can feel everything.”

Leaning down over her body, Shining surprised her with a brief kiss on her still-sloppy lips. “Only the best for my Twiley.” He flexed his hips, and his cock sank deeper inside her.

Twilight's back arched, stretching her belly out underneath him. He couldn't help but touch that long, gorgeous curve ... and then follow it upward to her nice firm little breasts.

“Give it to me, Shining!” She hooked her legs around behind his ass. “I've waited a whole year to feel this again, and I'm not waiting a second longer!”

Smiling, he obliged her, pressing himself the rest of the way in. Just as his sheath pressed against her pussy lips, she let out a little gasp as he touched her innermost barrier.

She grinned up at him, despite the blindfold. “Perfect fit, as always.” Her pussy clenched and unclenched around his shaft, massaging his brotherly gift to her.

If only he could take a snapshot of this moment and capture it ... if only he could relive it again and again whenever he wanted to... Twilight's secret little smile and the way she looked at him from behind her blindfold, her cute little body laid out perfectly in front of him, the inner walls of her pussy hugging his cock like a long-lost friend... His brain was certainly taking a snapshot of it, anyway. He knew from past results that today would be stuck in his head for a long time. For months to come, he'd be thinking of Twilight like this every time he jerked off, every time he came inside his wife. And he wouldn't want it any other way.

Twilight squirmed a little against the bed sheets, giving a slight moan. Her warm pussy clenched around his shaft again.

He'd been lost in thought for too long, mesmerized by staring at the perfect picture in front of him – he'd neglected his sister's needs! Hastily, he started thrusting inside her, and the sexy little sounds from her mouth changed from needy to ecstatic. His own knees felt week from the pleasure of his sister's pussy lips sliding up and down the sides of his cock. The soft, sloppy-warm grip inside her seemed to be begging him for his release, even more than Twilight's gentle moans.

Every one of Twilight's panted breaths made her adorable little belly flex, made her little boobs jiggle, their nipples jutting straight up as her fur began to stand on end. Her pussy started to clench harder as she already neared another orgasm.

Shining couldn't hold himself back much longer, either. His hands slid up from his sister's hips to grip around her trim little waist ... she felt so small, it felt almost like he could wrap his hands all the way around her. And it felt like he was jerking himself off with her, using his precious little sister as nothing but a cock sleeve. His thrusts became shorter and grew more frantic; he felt the tightness around his tip as it swelled, flaring up inside and creating a perfect seal around the entrance to his sister's womb.

“Do it!” Twilight cried out. “I want it, Shining! I want it so much!”

Even in his nearly-orgasmic state, though, Shining knew that was just her arousal talking. There was no way they could risk a pregnancy – that was one sibling-to-sibling boundary that he would not cross.

With a little difficulty – and a mountain's weight in willpower – he yanked himself back. His flared cock squeezed out of his sister's pussy, just in time.

“No!” Twilight's pussy clenched down on nothing, too late now to trap Shining's broad, flared tip inside.

Shining laid his glistening-wet cock against his sister's belly and threw his head back, groaning as the pressure finally burst. It throbbed against her belly, and the first thick pulse of cum shot out onto her chest, coating the undersides of her perky little tits.

But Twilight wasn't about to let it all go to waste. She grabbed his cock with her magic, tilting it upward a little as she opened her mouth wide and stuck out her tongue.

Her aim was impressive – especially for a blindfolded mare. The next stream caught her mostly on the cheek and across the bridge of her nose, though she managed to move and get the last little bit of it in her mouth. Every spurt of cum after that – and there were a lot of spurts – went almost perfectly into her waiting mouth, pooling there and splashing out when there was too much to hold. Of course, she did miss a little bit. Extra splatters fell on her breasts, her neck, her mane ... one thick splash even glopped onto her blindfold, seeping into it and creating a darker spot across Twilight's eyes.

Shining watched it all, his mind throwing up fireworks of pleasure with every throb, with every drop that landed on his adorable little sister.

But even with such an incredible view, his orgasm couldn’t last forever. Soon, the cum shooting out didn't have enough power left to reach Twilight's mouth. Each successive little spurt landed lower down on his sister's body – her valley between her outthrust breasts, the subtle curve at the bottom of her ribs, and finally just dribbling out where the wide-flared head of his cock was held by her magic just above her belly button.

Twilight looked at him – despite the blindfold, he could tell she was looking straight up into his face – and she closed her mouth. Her throat bulged slightly as she swallowed, then she opened again, showing him her lips and tongue almost entirely clean again.

Shining shuddered with pleasure at the sight, releasing a last little dollop of cum that splatted onto his sister's tummy. When she released his cock from her magic's hold, it fell down heavily, flopping against the feminine curves of her belly, the head of it floating on the little pool of cum in her belly button.

For a few moments, all he could do was tremble in place and try to keep breathing. His cock slowly shrank back toward his sheath, sliding down Twilight's belly along the way. He made sure it didn't slide directly over her pussy – drops of cum still clung to it, and he didn't want to take the slightest risk of some of it getting inside her and making her pregnant with incestuous offspring.

As sexy as Twilight looked, lying there soaked in his cum, her hips jerking upward as if to hump against him, Shining knew she must have been getting uncomfortable from her tied-up position. Bracing himself against the side of the bed, he rolled her halfway over and undid the loose knot of silk binding her arms together behind her back.

The moment she was free, she sat up and took off her own blindfold. The look she gave Shining the moment he saw her eyes smouldered with a deep satisfaction and unfathomed love ... but the slight quirk of her eyebrows and the way she licked her lips slightly spoke of how she was denied that last orgasm – one that would have no doubt been triggered by feeling him cum inside her.

Shining gave her a little kiss, ignoring the splatters of cum on her muzzle. “Oh Twiley,” he said, “you're so irresistible when you look at me like that.”

She glanced down, though, at his cock and how it was almost entirely back in his sheath now. Strangely, though, she grinned ... an almost malicious-looking grin.

He backed away slightly. “Twiley ... what are you planning?”

“Not planning, actually – executing a plan I came up with months ago.” For a moment, her horn flared. A tiny glass vial teleported into the air in front of her and fell into her hand. “Here, drink this.”

Shining took the vial from her hand, but he didn't drink it, not yet. He held it up in front of his face, examining the thick, milky liquid inside. It flowed like syrup, but was a slightly off-white color. When he popped the cap off the vial and sniffed it, he immediately jerked back and held it away from himself. “Ugh! It smells like cum!”

“Well, yeah.” Twilight rolled her eyes. “What else would you expect to be the main ingredient of a virility potion?”

“A virility potion?” He looked at it again, still holding it far away from his face. “Is that my cum in there?”

She waved her hand dismissively. “Of course not. The ingredients have to be fresh, and the potion only has a shelf life of a couple weeks.”

“Then whose...?”

Pushing his hand – with the vial – back toward him, she clasped his other hand. “It doesn't matter whose cum it is. Come on, BBBFF! Can't you see how much I'm suffering here? Drink it, and let's go!”

He held it closer again. The smell seemed even worse now that he knew what it was ... and it wasn't just cum-smell. There was something sour in there, and bitter as well. “I don't know...”

Twilight stood in front of him, his cum dripping off her body as she posed, hands cupping her breasts and legs slightly spread, showing off the still-clean mound in between them. Her tail flagged high behind her. “Come on,” she said. “We can't let your refractory periods get in the way of the precious few hours we have together before Sharing Day is over! If I can swallow a gallon of your cum, you can drink one little potion. Zecora guaranteed me that it's safe. Just hold your nose and drink it!”

Looking at her like that, the point easily drove home into Shining's head – the idea of the potion might be a bit unpleasant, but the reward for drinking it was on obvious display right in front of him. Just the sight of her was starting to make his cock slip out of his sheath again, almost as if he didn't need a potion at all.

But he did what she wanted, held his nose, and downed the potion in one quick shot ... despite the way it clung to his throat and burned on the way down.

By the time he took his hand off his nose and set down the empty vial, his cock was already raging hard again, jutting out prominently toward his sister.

And she didn't waste any more time. Pushing him back onto the bed until he sat down on the edge of it, she leapt up onto his lap and plunged herself down on his renewed cock, tilting her head back and moaning as the entire length of it slid inside her and she came to rest in his lap.

Shining grabbed his sister's cum-sticky tits as she began rocking her hips back and forth, working his pussy over his good-as-new cock.

He could tell – this was going to be a good Sharing Day.

Author's Note

This story was chosen by my Patreon supporters! Every month, I take suggestions from my supporters and let them vote to determine which story I'll write next.

If there's something you've been dying to see me write, please go to my Patreon page and sign up to be part of the suggesting and voting process.

Chapter 2 will be published tomorrow. Further chapters are not yet written and may take a long time to appear.