Secret Sibling Lust

by Nagiman

Rating: mature
Tags: Twilight Sparkle, Alternate Universe, Porn, My Little Pony: Friendship is Magic, Fetish, Shining Armor, Sex
Length: 5268

Twilight Sparkle and Shining Armor are left alone for the weekend while their parents are out. With them alone, things come to a head as Shining's secret gets discovered.

Twilight Sparkle, Student of Celestia, and Shining Armor, soon to be Militant, are left alone in the house for the weekend. Their parents are out for their anniversary and leaving the pair behind. Trusted to not make a mess of the place, the pair start with a rough little stint until Twilight feels her heat coming on. Not wanting Shining Armor to get a whiff of her smell, she backs down. Soon after Shining leaves an item alone and forgets about it, leaving Twilight to discover a dirty little secret. Things soon become wild for the siblings as feelings spill out in lustful actions.

Contains - M/F, Feral, Incest, Twicest, Shining/Twilight shipping, Sex Toys, Masturbation, Assisted Masturbation, Anal Insertion, Thigh Job, Vaginal, Condom Usage, Brother/Sister, Double Penetration using Sex Toy, Squirting, Mare in Heat

Inspired by Selenophile's latest NSFW Comic
Cover art by Selenophile >>>1469468 Warning NSFW Image in Full

Published 2022-01-30 23:30:01 UTC
Last updated 2022-01-30 23:30:01 UTC

Curious Discovery

The front door to the Sparkle residence closed with a click, leaving the two siblings standing there with each other as they finished wishing goodbye to their parents for their anniversary weekend. Shining Armor with his coat of white, hair of mixed blues, and light blue eyes, and Twilight Sparkle, her lavender fur, with a mix of blue, purple, and pink hair, finished with her purple pupils. Both of them knew better than to start a squabble in front of their parents, but as soon as the sound of them out of the driveway was the signal that it was all fair game.

"Finally," Twilight let out with exasperated relief, "Shining, don't you dare start a party, or loud noises, I have to study for a test on Monday. If you try anything funny I'll make sure Mom learns of you ogling the older mares around town and the little stash of pictures you've been gathering." Twilight put on a wily smirk as she flicked her tail in her turn around, her head held high in pride.

Shining's jaw dropped down at the threat of his secret. "Don't you dare try that Twily. I've got proof of you doing late-night experiments with Spike again after you've been told to be in bed. I'm sure Dad would love a chance to remove your equipment from that spare room for the little lounge he wants." He marched forward and cut his sister off, his head lowering to hers and locking eyes in a battle of dominance.

The pair stared at each other with little fits of sibling rivalry, horns flaring little sparks of magic as they leaned into each other. Twilight backed down after a few more moments as she felt a sharp flash through her body right to her nether region. Her tail clamped right close to her rear as she took those few steps away. Turning her head with rosy cheeks and pride still clung to her face. "Fine; I think we can agree to disagree, but still no parties. I have to be ready for that test or else I'll look bad to Princess Celestia. Besides, shouldn't you be getting ready to head to the academy next week as well."

The stallion's eyes went to pinpricks at the mention of the academy. "Crap, I forgot all about it. I need to get things packed up and ready." His hooves bounced in place as panic set into his head, taking control like a puppeteer. He turned and took off running to his room, leaving his sister behind in the living room alone.

Twilight stood in the silent room, with the sound of the clock ticking as the seconds floated away. Her body heated like an oven, as her vagina dripped just a few drops of sexual fluids onto her leg. She clamped her teeth onto her lip as she felt her sexual urges overwhelming the strong mind she built. Shaking her head, she shuffled her way to her bedroom to be out of sight and smell of Shining Armor. Once inside her quarters, she let her tail free of the press it had over her genitals, letting the heat breathe in the cool air and sending tingling delight throughout the mare. Twilight rushed over to her bed and jumped onto it, opening her nightstand's drawer to pull out a mottled black and pink stallion-shaped dildo, with a matching set of molded balls at the end of the shaft.

The silicone object wiggled in the air as the magic holding it moved it over to the purple pony laying on the bed. It swayed to and fro as Twilight brought it to her mouth, kissing it with her lips before opening wide and sucking on the fake phallus. Her lips coated the length with saliva drooling from her like a fountain in a park. Her fevered motions of fellatio to the dildo caused her to get it stuffed into her throat, sending her into a small gagging fit as she pulled it out and coughed out some more spit onto herself. Her chest rose and sank as she took a moment to regain her breath, her vision blurring and forming an imaginary vision of her brother, Shining Armor, standing over her, his dick at the ready.

"Oh Shining, please rut me. Get this heat away from me," she whispered to herself before she lowered the dildo down to her puffy leaking pussy. The rubber rutting device rubbed against the puffed lips in a teasing manner, sending jolts through Twilight's spine. Biting her lip in anticipation of the penetration; it was always her favorite feeling as she only used her toy when the heat hit her. With gentle ease of her magic, she guided the tip of the toy between her labia, spreading the small petals of her flower open and slipping the device into her wet canal. The lubrication from her sexual juices was more than enough to let the toy in, but her spit added to her bliss of having given minor fellatio to her partner.

Meanwhile, Shining Armor was busy in his room, packing his suitcase with all his military outfits, grooming tools, and anything that he would need for his time at boot camp. His panic-stricken mind prevented him from hearing the sounds coming from the room across the hallway. His hooves worked like a flurried hurricane that the pegasi would have been proud of. Each moment that passed, his bags became fuller as his dresser became emptier. At the bottom of one of the drawers, he spotted something purple sticking out from beneath part of one uniform. He reached down and pulled it out and was greeted with a purple pussy made of silicone. His face flushed red with embarrassment from the sight of the sex toy in his hoof. "I can't believe I nearly forgot about this. Glad Twily never found it, let alone mom. I guess I'll have to throw out it before I go." He looked around his room as if he was being watched before taking a few steps towards his door.

As he reached toward the knob, a thought came across his mind. "Well, maybe one more time would be fine. For old times sake." He eyed the toy again, looking at the design of the well-made mare bits, with a winking fake clit sticking out. It was covered with a bit of dust and lint as he rotated the toy around. "Should give this a clean first though," he said to himself as he opened the door to his bedroom. Slipping into the bathroom next door, he closed the door behind him and turned on the sink, running the warm water. Slipping the toy into the sink to be bathed in the flowing liquid, he opened the bottle of soap and let a small amount out onto the toy and a smaller amount to the inside of it. He played around with it with his hooves to get the soap to spread through the center of the device before letting the water spray inside and create a foamy discharge. The foam solution flowed out the other end of the toy, down into the drain as the water kept flowing through. Once the soap stopped coming out of it, he grabbed a nearby towel and set the toy wrapped in it onto the counter. "There, I'll let that dry for a bit and then I'll have fun once Twilight goes to bed."

Shining left the bathroom and returned to his room to return to his packing. The toy sat there in the white towel, the moisture to be absorbed by the cotton material. Unbeknownst to the stallion, his little secret wasn't going to be so secret anymore.

Twilight flipped herself onto her stomach, letting her magic autonomously control the dildo as her hooves gripped onto the headboard of her bed. She let out moans of delight, with little squeaks now and then, and with small callings for Shining Armor as she rammed the toy deep into her aching pussy. Her tongue hung out to the side of her lips as she pushed and pulled the penis, its semi-flared tip tickling the inner walls as it moved. She clamped down around the shaft with her muscles as she felt the faux balls tapping against her winking clit. Her tail raised higher as she became more enamored with her playtime. "Fuck Shining, give your little sister a ride. I need it badly." Twilight moaned out as she put her magic into a wild frenzy, her pussy being jammed with the phallus at a high rate, with juices spilling out around it as it moved.

Rolling onto her back, she placed her front hoof onto her clit and began to rub it as the dildo worked her insides with intense rhythm. Each stroke sent joyous signals to her brain, while the stimulation of her clit clouded her thoughts with more and more depravity of her older brother rutting her. The vision of him sweating above her as he forced his hips forward to slam his dick deep down into her. Her moans grew more and more as she went to town with the speed until she stopped with a hard slam deep into her womb. With a scream, followed along with a sizeable squirting of her marecum all over the bed, Twilight, reached her orgasm. Her body convulsed with pleasure, her hind legs tensing hard, her vagina clamping the dildo into its new temporary home, her tail flicking side to side, and her neck straining back. Her eyes rolled into the back of her head as she leaned deep into her pillow.

The scream echoed from Twilight's room into Shining Armor's. This time Shining picked up on the loud noise walked out over to his sister's room and knocked on the door. He listened for a second before giving a light shout through the barrier. "Twily? Are you okay in there? I heard a scream." He stood there with an ear against the door.

Twilight sat up in a small panic, with her hooves over her mouth. Realizing that her brother heard her scream, her heart raced like a car speeding down the street. In a wild panic, she threw herself to the ground, the dildo still sticking in her. She quickly walked to the door and cracked it open slightly. Her face beat red, with hair in a fluster, she gave her brother a cheeky smile. "Everything is fine, nothing wrong here. Just some frustration at a problem." She let out a nervous chuckle as she tried to maintain her weak illusion.

Shining eyed her for a little bit before shrugging it off. "Alright then. I'm still packing, but I'll be cooking something when I'm finished. Just try not to bring down the house in your quest for knowledge."

"Don't worry, I'll make sure not to take down the walls." She gave another nervous laugh. "Now if you'll excuse me, I have some... studying to get done." She closed the door quickly and put her back against it as she listened to her brother's hoofsteps fade away with his door shutting behind him. Letting out a sigh of relief, she slid down the door onto her butt, causing the dildo to poke fully back into her womb, giving her a small shock. She jolted upright immediately with the scare. Talking to herself she walked back over to the bed, "Thank Celestia he didn't probe further. The last thing I need him to know or hear is me screaming his name." She looked over her wet bedsheets coated in her sexual excretions. She frowned as she pulled out the dildo and set it on top of her nightstand. "I hate the cleaning afterward. Always feels wrong having to clean them." The smell of sex wafted from her rear into her nose as she gathered the sheets in a ball with her magic. "Maybe a shower while these clean will be good as well. At least my heat is better now."

The white stallion worked away diligently in his bedroom, his ears tuning out to the sound of the bathroom door closing. His mind was too focused on finishing his packing. Meanwhile, Twilight carried a magical ball of blankets into the bathroom setting them into the washer and setting them to work. While the machine started up, she turned on the shower water to let it warm up as she went to grab a towel. Seeing the white folded towel on the counter she reached for it with her hoof and felt something squishy inside. She looked at it with a bit of curiosity and a little bit of caution. Unfolding the towel revealed the masturbatory toy inside, giving her a surprise. Taking a few steps back, Twilight's heart tried to calm itself from the shock of seeing such a thing and in such a color. It matched her tone for tone, both inside and out.

"What in the world, where did this come from?" She walked back toward it, picking it up with her hoof and eyeing it over. She pulled the lips aside to see the ribbed inside with pink flesh-like color to it, and the well-made clitoris that was part of it as well. It felt odd to her to hold such a thing, especially since it looked like her. Then the thought came to her mind, this was Shining's toy. She set it back down onto the towel, taking steps back away from it before sitting on the floor. "So, Shining has a crush on me, his sister." She felt her heart flutter, as her nether's winked in delight. She looked around the room before standing back up and grabbing herself a fresh towel from the cupboard. Hopping into the shower, she set about forming a plan, something that would help her heat, and give her brother something before he leaves for the academy.

Time had passed and Shining finished packing up all his things for the academy. Wiping his brow from the sweat and looking over his room, he felt proud of his work. His stomach let out a growl, interrupting his blissful moment. "Guess I should eat, maybe just a sandwich," he thought to himself. Opening his door he heard the sound of the washer going on in the bathroom but thought nothing of it as he headed towards the kitchen. As he turned the corner and disappeared into the kitchen, the bathroom door opened and Twilight stuck her head out, seeing if Shining was nearby. With the coast being clear she rushed over to her room with the toy wrapped in the towel in tow. Shining being completely oblivious to what his sister was up to, went about his time getting a sandwich made and headed to the living room.

Inside Twilight's bedroom, she was busy getting her plan into action. She set Shining's toy onto her bed while she went about getting set. "Now where did I put those things," she said as she dug through her bins stored in her closet. Digging around through three bins of things and finally on the fourth finding what she was looking for. She pulled out two pairs of white and pink striped socks, with a pair of white panties with pink hearts spotted around them, with light frills on the edges of the leggings. "Perfect, he's going to love these. Now, where did I set those other things." She continued digging through her room, making as little noise as she possibly could.

Out in the living room, Shining Armor sat on the couch finishing off his food while watching a hoofball game on the tv. His stomach was now filled with delicious goodness, and his mind was completely at ease as he leaned over the edge of the couch. His eyes felt a bit heavy as he watched the game, the sun setting through the window sill, and the quiet sounds of a near-empty house all making a much more relaxed atmosphere. He snapped awake when he heard Twilight's voice echo from the kitchen area.

"Shining, are you in the living room?" Her voice had a tone of stern but yet relaxed to it.

"Ya, I'm just watching a game. Do you need help with something?" He responded, a bit bewildered by such an obvious answer.

Twilight peeked her head around the corner, a big smile across her face as she looked at her brother. "Yes and no." She walked around the corner showing off her socks and panties as she entered the room, her magic holding Shining's toy behind her. "Just that you left something in the bathroom." She floated his sex toy out in front of her towards Shining.

The stallion gasped, his eyes going tiny at the sight of his little sister holding his sex toy, let alone one that looked like her. He jumped off the couch and went to grab it from her but was denied by the magic pulling it out of his reach. "Twilight, I can explain. It's not what..." he got out before having a hoof placed over his lips.

"No need to explain, I understand that we can all have urges that need satisfying. Besides, I'm a little interested in why it's the same color as me." She said with a smug tone as she trotted over to the couch. Placing her front hooves up on the seat of the couch, she bent down to raise her rear a bit higher into the air and slide the toy between her thighs, just under her pussy. "I know what you want Shining, but I'm not going to give it up that easily, however, I can offer something at least close to the real deal. Go on Shining, show me how you'd like to rut me." She swayed her tail back and forth, giving small glimpses of her panties, slowly staining with her fluids.

Shining looked at the display of prowess in front of him, the pose, the outfit, the sexual teasing in a passionate execution by his little sister. The toy itself seemed to be dripping out clear liquid already, pre-lubricated for him to use immediately. He felt his heart jump, the beats pounding in his ears like a drum, and the wetness of his saliva filling his mouth. His sheath gave a twitch as his length began to harden with the teasing. His mottled cock slipped down and out, and back up to full mast as he took steps towards his sister. He lifted himself over the top of her, his hooves gripping onto her hips as he used his magic to line up his cock with the toy.

Twilight felt the weight of Shining on her back, his baited breathe tickling her neck as he took his time. Then came the small push against her legs as the toy was opened with his shaft. The rod's stiffness pushing against the silicone and her inner thighs felt strange but in a good way. It was nice to have her brother be himself with her, even if it was through assisted masturbation. His dick moved in and out of the toy, and rubbed against her thighs with each of his thrusts, pushing her forward when he went in. His face inches away from the back of her head as he made good on his sexual urges.

With his eyes closed, Shining imagined himself rutting his sister for real, his mind blanking the rest of the room away. In his mind, this was the real thing and was well worth the wait for it. He whispered out, "Twily, you're so tight. I can't believe we waited to do this." His words slipped from his lips and into his sister's ears.

The purple mare blushed at the words, ones that spoke that this was the truth she deduced. Her body ignited again like a bonfire topped off with gasoline. Her heart pounded louder than a damn in her ears, as her genitals went up in flame causing her to leak more fluids into the seat of her panties, growing the small little dot into a bigger puddle. She used her magic to hold Shining back for a second as she said. "Just a second Shining, I want to shift around." She felt her brother remove himself from her, giving her the ability to slip up onto the couch and pull her legs up, still with the toy betwixt them. "Alright, please continue."

Shining didn't hesitate and took hold of his sister's rear hooves as a balance as he stood on his hind hooves. His dick slipped back into the toy with ease, his hips swaying back and forth causing his balls to tap against the soaking fabric of Twilight's panties. "This is wonderful Twilight, I don't know what to say," he muttered out as he tried to keep a steady tempo with his thrusts. Each thrust felt so real, even though his tip poked out the other side of his toy, to him it was the best thing to have gotten.

"You could have asked me earlier, or told me about your urges. You know I'm always willing to try stuff for science." She giggled a bit as she watched her brother turn beet red in the face. With the newfound angle, she found that her teats were getting a gentle rubbing as well, and despite how small they were, her nipples grew erect from the attention. "Oh Shining this feels wonderful." She let out little moans of pleasure as her brother grunted with his now deeper but slower thrusts.

His panting picked up as his lungs burned from his heavy breathing, his muscles equally as sore from the position. He felt his orgasm building up for release, gently biting his lip he tried to hold it back as much as he could. "Twily, I... I'm gonna... gonna..." he got out before the floodgates broke and his orgasm flowed out of him with great speed.

Twilight's face was sprayed with the first stringy rope of the white cum, it landing on her nose and hanging down to her mouth. In response, she opened wide and let the rest of it fly into her maw. The salty-sweet fluid landed directly onto her tongue and some down her throat. It tasted just like a dream to her, as she swallowed down the bits that hit the back of her throat. Her ears were filled with the moan of delight from Shining as he unleashed more and more of his cum into and onto her. Her chest fur got a light sprinkling of the fluid, sticking into her coat and making it just as sticky.

Shining opened his eyes and watched as his orgasm slowly died down. Watching as his sister took his cum like it was her millionth time doing some, and the white that she was turning from the bits landed on her. With one last dribble, his orgasm was spent. He let go of Twilight's hind hooves and landed on his front to try and keep his balance. His aching muscles tried to keep standing until he dropped down to the floor laying on his back. "That was amazing Twily. I'm so glad you let me do that." His chest rose and fell as he stared at the ceiling.

Swallowing the last load of her brother's cum, Twilight slipped off the couch down to her brother's side. She looked him up and down, with the toy still attached around his shaft she pulled it off with a sloppy wet plop. Her smile spread wide as she gave Shining a kiss on his forehead. "I see you do care about me. So I think, if you can that is, we should go for one more round, but this time with the real thing." Stepping over her brother, her ass towards his face, she pulled down her panties with her magic to show off her dripping pussy, and her dildo shoved deep into her pucker tailhole.

The smell finally hit Shining's nose and revved his engine to get his shaft at full again. "Twily, you're in heat. We can't do that, you'll get pregnant, and I'm sure mom and dad would kill us for it." His face tried to look away, but his eyes remained glued to the glorious purple plot sitting not too far from his face.

Twilight lit up her magic and pulled out a blue square from inside her sock to hover it in front of the stallion. "I know, but with this, we'll be fine. Mom gave me a few just in case things ever escalated at school and I needed them. I've never used them before, but I think now is a perfect time." She floated the condom towards Shining's dick and opened the package. Pulling out a light pink condom from the package, she lowered the rubber device over his tip and began to slowly massage it down. As it unraveled, little bumps popped out around the condom, more and more appearing as it got lower and lower onto the phallus. "There, I think that should be good enough. Don't move, this time it's my turn to make you feel just as good, but could you play with my dildo. I've always wondered what double penetration would be like."

Shining nodded, as he watched his sister move forward enough to have her rear lined up with his groin. His shaft was fully erect and waiting for the sweet taste of a real pussy. The warmth flowed from it as it got closer, sending tingles up his spine in anticipation of his penetration into a real mare for once. As his sister pushed herself down onto him, he felt the tightness compared to the toy and it was night and day to him. It squeezed him as she lower, the warm insides giving a welcoming feeling, and the wetness much greater than his lubrication. When Twilight reached the medial ring on his shaft, she pulled up and began to sink back down again, repeating this process a few times before going a bit lower. The soft stroking feeling amazing, causing Shining to moan out in pleasure in unison with Twilight. Following the polite ask of his sister, he used his magic and took hold of her dildo in her ponut and started to stroke it in and out of her ass.

Letting out a squeak of delight, Twilight relaxed to the feeling of fullness of both her holes. The little bumps of the condom on Shining's dick gave a nice addition to his bigger girth compared to her dildo, scraping the insides of her walls and hitting pleasure spots she didn't know she had. The dildo was also hitting these subtle spots she didn't think would be possible in her tailhole but still melted to the feeling of them being pressed. "Fuck Shining, just like that. Don't stop," she moaned out as she rode further down onto the dick deep into her vagina.

His sister's pussy clamped down onto his dick again and tried to milk it as she bottomed out onto his groin. It felt as though it was vibrating with the contracting motions it made as she stayed there for a few seconds before going again for another bounce. Her soft cheeks landed gently onto his thighs as she rode him up and down. His magic worked away at the dildo when he decided to make it vibrate inside her little ass. This caused her to scream in joyous bliss, causing Shining to receive a pleasurable response from her pussy doing the same to his dick. The feedback loop caused both siblings to feed into their inner urges.

Twilight rode harder and harder onto her brother's dick, As Shining worked the dildo faster in his sister's asshole. The twinning response caused their heart rate to rise to extreme levels, with euphoria taking hold of their bodies. Each second felt like hours as they continued with their feral rutting. Juices dripped from Twilight's pussy like a fountain down onto her brother, as Shining's flare expanded and pushed against the inner walls in response. The pair of them reached their orgasmic limits with each other.

With a few more pushes of the dildo into Twilight's ass, she broke down into a scream of joy as her pussy squirted hard, soaking Shining's balls in her slick marecum. Her pussy milked away at the condom-covered cock in hopes of receiving the sticky cum sitting inside his shaft.

As Twilight's motions stopped and her vagina went to town on his dick, Shining busted his load into the pink condom. Inflating the rubber, like a balloon with the copious amount of sperm rushing from his tip and trying to escape. The sticky fluid filled in the tip and expanded it out as his flare acted like a plug, preventing it from flowing back down. He grunted as his hooves wrapped around Twilight's hips, keeping her steady and from falling off of him. The combined warmth gave him shivers of bliss.

Time passed, and the siblings came down from their orgasmic highs. Twilight released her brother's dick from its soft velvety prison as she pulled herself free from the now shrinking shaft. Her breathing was at a slower pace as she took in deep for a few seconds at a time. She then pulled the dildo from her butt, feeling the stretched hole trying to collapse back into it's normal perky puckered shape. "Shining, that felt amazing. Even better than just using my dildo." She lowered her head next to his and gave him a nuzzle.

Shining lay there, drained of energy and the ability to move his muscles. The intense rutting session had taken its toll on him. He managed to pant out, "Same to you Twily." His eyes shut closed as he drifted away to sleep.

Twilight smiled at her snoring brother before turning to the mess they had created on the floor. She frowned at the sight of it and thought to herself, "Tomorrow Twilight, you can clean it then." She went to turn away but her eyes caught the sight of the ballooned cum filled condom still hanging to Shining's sheath. Lifting it off his dick, she brought it to her eyes, it was about the size of a baseball with the amount of cum he blasted. Not wanting to throw it out, she slipped the open end of the condom into her mouth and lifted the filled end to drain it into her maw. The sticky fluid dripped down into her mouth and down her throat, swallowing each drop as it flowed into her. With a few good chugs, the condom was drained for the stallion cream, leaving behind just the stretched rubber shell coated with her juices.

Walking towards her room, she threw the condom into the trash. Her mind went through what she wanted to do tomorrow after studying a bit more. After all, they still had one more day before their parents were going to return, and one last chance for them to have fun before Shining left for the academy. Her heat quenched for now would need to be calmed again, and maybe this time they'd get to try something else as well. Twilight closed her door behind her and jumped into her bed. Her eyes became heavy with sleep as the rest of her body sunk into a deep drained state.