Shinning Armor lay in his bed restlessly as he thought about the looks and touches of his sister Twilight Sparkle, his mind clouded with visions of their past, moments of indecent pleasures and forbidden passions. His sister had come to visit him for the weekend while his wife was out on royal business, Twilight having arrived early enough to share an early dinner with them both before she had left. However during most of the dinner, Twilight had kept her eyes on the stallion, a deep, wanting stare following his every move. The gazes had gotten to him, the stallion forced to keep concentration in order to avoid falling into her spell. He had gone through great effort to hide their past from his mind, especially now that he had a lovely wife of his own. Twilight seemed hell bent on persuading him otherwise though, her looks soon progressing to light kisses on the cheek, a little too smooth to be sisterly, and even a rubbing of his leg under the dinner table.
It all reached a burning peak when they had given their final waves to the disappearing train that took Cadence away, Twilight braving one more kiss in plain sight. Shining Armor could still feel it clearly, the slight momentary peck on his backside. He had to focus beyond any measure he had before to keep his cock from getting rock solid the rest of the evening, thankful to Celestia when it was finally time for him to retire to bed. His sex life with his younger sibling had been so fiery, so raw and taboo, that even in his married life he found himself thinking back to it. His cock was rock hard as he lay under the covers, thinking about the actions of his sister, left to stew alone in his thoughts as his wife kept somewhere else, many miles away. Anxiety was flooding the poor stallion's system as he stumbled through many an inappropriate thought, the only break to his stewing being the creak of his door slowly opening.
He could not make out who it was in the darkness, but he could venture a guess. Within seconds the intruder had slid silently to his bedside and snuck under his covers. Shining Armor closed his eyes and whimpered as he felt his sister slide up against him, her hooves rubbing gently over his heavy shaft. "Mmm, were you thinking of Cadence brother?" Twilight whispered into his ear before giving it a nip, "Or me?"
"Please don't do this Twilie" Shining whispered to her, the head of his cock leaving her hooves sticky.
Twilight ignored his plea, still rubbing his length smoothly, "You still look at me like you did when we were foals." She slid the covers off just a tad, reaching down to kiss the salty head of the stallion's shaft, "Your body isn't even hiding how much it wants this!"
"Twilie, I-I can't anymore, you know this. Cadence is my wife, Cadence is m-my mate, my love, Cadence-"
"Isn't here right now," Twilight finished her brother's statement for him as she swallowed a good amount of his shaft down, gulping it down smoothly as she began to bob her head in a quickening rhythm, "So why don't you just let little Twilie take care of you?"
"This is wrong," Shining gasped as Twilight kept sucking him off, soon reaching down to slurp on his balls, "This is so wrong!"
Twilight suckled on the firm orbs, letting them go with firm tugs before whispering, "That's why you love it so much isn't it?" Her brother simply whimpered more. "You love the idea of being a dirty stallion, fucking his little sister while his wife is gone. His sister that knows his body far better!" She hoisted his legs up and looked over his tight pucker, "Did you manage to convince Cadence to do this for you yet?"
Shining suddenly tensed up as he felt his sister's breath hover over his rump, her tongue gliding slowly over his soft musky hole. "T-Twilie, ahh, ahh!" Her brother was unable to hold back his desperate moans as she dragged her tongue up and down in slow slides. "Twilie, g-god, don't stop!"
"What about your wife?" Twilight teased, knowing how easily she had won, her tongue plunging deep down inside his warm hole. She slid it around in slow, teasing circles, stretching his pucker out slowly with hungry dives of her tongue.
"P-please don't tell her... oh god, Twilie!" The stallion's cock twitched as drops of precum dripped from his head, somewhat flared as he gave up his will and control to his temptress of a sister, "Just please, don't stop!"
Twilight looked up at her brother as he turned and lay back, eyes locking onto his as they squinted, her nose nudging his balls as she kept plunging her tongue into his backside, "Mmm, it's so tight brother, has Cadence not been taking care of it?"
Shining Armor blushed and tensed up, "W-well, she h-hasn't really tried this before..."
"Oh gosh, you poor thing," she teased as she kept licking, tongue circling before she would dive in with her muzzle, getting the hole allow et and loose for her, sending tingling pleasure rushing through her brother, "Does she at least let you do the other things you like?" Shining Armor simply blushed, hesitating to answer. Twilight gasped, "You poor thing, don't worry, little Twilie is here!" With that her tongue dove all the way inside him, the stallion groaning hungrily until she slid the slippery muscle to his balls, sucking on each orb firmly. She then worked her way back up his shaft, lathering the underside of his heavy shaft in salvia before lapping any salty trace of his precum up. She suckled on the heavy head of her brother's cock, slowly pleasing him before swallowing his whole length down in an eager gulp.
"T-Twilie, my god, I've missed this!" The white stallion sighed as he clutched his purple sister with his hooves, feeling her warm, tight lips swallow him down with ease. There was a rhythm to how she tended to his needs that Cadence had never quite found, and although he loved his dear wife greatly, Twilight would always be the one that owned him physically. She kept gulping his cock down over and over, smoothly, slowly, then faster, tighter, until her brother was left in a melted pool of satisfaction, his moan low and desperate as he fired his first load down his sister's throat. Her wings flapped gently as excitement filled her eyes, the cutest look of joy in her eyes as she gulped down every last strand of salty seed that was gifted to her.
She pulled tightly on his flared head as she backed off, licking the last strand from his cockslit as she whispered, "Delicious." He looked at her with a blush and she added, "I know you're good for more than one of those, so you'd best get ready again for your dear sister!" Shining gulped as Twilight's teasing already cause his cock to stir again, watching as she turned to show off her backside to the stallion, "What does big brother want to do now?"
Any attempts at holding back his lust were now thwarted as his sister had but her plot in his face, suckling on his slowly stiffening shaft again. "I w-want to fuck you!"
"You want to fuck me?" Twilight chuckled as she wiggled her rump, "Fuck me where?"
Shining Armor was practically brought to tears as he started lapping at his sister's pucker, so desperately horny, his cock now filling up the mare's muzzle again, "H-here!"
"Mmm," Twilight groaned as his tongue slid over her rear, "That's right, I remember now. Big brother always loved to play that game when he foalsat." Twilight grinned as she continued her third person commentary, "He would wait until we were all alone then put his thingy in my butt. Hell, for the longest time I didn't even know my pussy was meant for sex, I thought all fillies and mares took it up the ass!"
Shining took a break from rimming as a tinge of guilt hit him, "I'm sorry sis."
"Don't be," Twilight chuckled as she lapped at the stallion's thick cockhead, "I happen to adore anal thanks to you," her tail whipped as she turned, slowly sitting on the stallion's shaft, "...and I wouldn't change it for all of Equestria!"
"Oh sweet Celestia!" Shining Armor cried out as he felt the intense tightness of his sister's rump, lubricated only by their combined saliva as its warmth clutched the fleshy pole during her gracious drop down onto it, "Twilie, you-you feel amazing!"
"Better than Cadence?" Twilight winked with a chuckle.
"I-I've never been inside her ass..." Shining reluctantly admitted.
Twilight faked a look of shock, "You poor thing. No wonder you feel, ahh," she wiggled the rest of the way down, "S-so pent up. I love Cadence dearly but she really should treat you better."
Shining moaned as Twilight started bouncing in his lap, her ass swallowing his cock down in hungry slides, covering it in soft warmth, "I love her, o-our love is far beyond just physical!"
"I know dear brother," Twilight said earnestly with a smile, "Your heart shall always belong to her..." She paused as she increased her speed riding him, her horn lighting up suddenly as she caressed the stallion's balls with a bright pool of magic, "...but don't you ever forget who your cock belongs to!"
"M-my cock belongs to Twilight Sparkle!" Shining Armor cried out patiently, panting as he rode her tight ass.
"Very good!" Twilight cried as she tightened her muscles, trying to milk her brother's thick cock, "Now are you ready to fill my tight little hole, or do you need me to tongue your ass a bit longer?"
"Oh god Twilie, mmmf you're so naughty!" He slammed up hard, pounding his shaft deep into his sister's hole, although he wanted more of the wonderful rimming, he was easily ready to burst. He slammed harder over and over, his cockhead flaring with each lunge. His balls tightened as he felt the pleasure inside him growing, an orgasmic pulse rushing through his lower body as he desperately humped his sister's warm ass.
Twilight let out a low whimper as his cockhead flared to a near unmanageable size, the thick length pounding up hard as he painted her bowels in a thick, creamy white. "Oh yes, yes brother fill me!" She cried as she bounced down on his lap a few more times, her stretched ass quivering as it was left properly stuffed. She rested on his slowly softening shaft and grinned seductively, wiggling her tush as she felt just how slick her insides felt, "Mmm, feels like you gave me a lot!" She squeezed hard enough to milk the lost drop, then pulled off of his cock, the flared head popping out of her audibly, "Good boy!"
"Twilight, you're so incredible," Shining Armor said with a smile, his sister grinning back to him as he seemed to forget the current situation surrounding them, almost returning back to the days of living back at home, "So wonderful, my little Twilie." He snuggled close with her before his eyes opened up, a look of shock filling his expression from his own actions, "That doesn't change the fact we shouldn't have done it though, why are you tempting me to do such awful things? Behind my wife's back no less!"
"I'm sorry big brother," she acted younger, her tempting eyes flashing as she tried to keep her brother's mind locked on the past, "I thought you liked this game..."
"Twilie..." Shining whimpered as he looked over her beautiful body. She had grown into such a beautiful mare, the geeky but charming unicorn now a princess of her own land, and a gorgeous Alicorn. Her attitude was less innocent like her old book smart self too, now holding the devious nature of adult corruption. He supposed he held most of the blame, having gotten them into such activities together at a young age, but he had always been the one in charge, and she had never been so ferocious in her appetites as she was now. He thought about what she offered that his wife didn't, and found himself unable to hide the look of want in his eyes.
"It's killing you isn't it?" Twilight Sparkle suddenly asked, Shining Armor looking back with a confused look.
"I'm sorry, wh-what is?"
Twilight's eyes were dark and cocky, "Not knowing when your ass will get eaten again..."
"Twilight!" Her brother replied in shock.
She flashed her eyes again, "Admit it, you love the feeling of a nice tongue up there, and poor little Shinie won't get it when his little Twilie returns home." The stallion winced as he felt his cock get slowly harder again, his breath desperate as Twilight spread out his cheeks and looked over his hole again, "Poor little plot."
"Twilie, p-please..."
"Hmm? 'Please' what brother?"
Shining winced again, "Please lick my hole again Twilie, I-I love it so much!"
"So... who does your ass belong to?"
"You" Shining whimpered.
"I wanna hear you say it!"
"M-My ass..." he began.
"...and your cock!"
Shining stumbled back into his speech, "My ass a-and my cock belong to Twilight Sparkle!"
"See," Twilight chuckled as she nestled her head down, tongue ready to spring to action, "That wasn't that hard was it?"
"What's gotten in-into-oh god!" Shining Armor's words were cut off as his sister began lapping at his pucker, little teasing licks at first before gently nudging in.
“I still remember, ahh, I tried this” Twilight began to regale in between slurps. “‘C’mon Twilie try it, it’s not dirty…’” She began to quote him in a mocked tone of his voice, stopping for a moment so she could ride his hole with her tongue, “I still remember how far you shot when I did it too. You came like crazy! I was so embarrassed to be licking your ass, but after a few times, I was hooked. Any time a handsome plot would trot by, my mouth would water, and as if that wasn’t enough, I was left getting wet every time you walked tail side in front of me. What would me kingdom be left to think?” she paused from her story, really giving herself to the rimjob. Her tongue plunged deep down and wiggled about, tickling every sensitive spot until his cockhead was flaring, “How would my kingdom react to dear leader Twilight Sparkle, visiting her older brother to shove her tongue up his asshole?” She did so again, and it did not take long before the pucker was clutching her tongue, Twilight squinting as Shining Armor painted her face white.
“T-Twilight…” Shining Armor could barely utter words as he lay in a melted pile, his sister grinning as she rubbed some of the mess over to her lips to swallow. What she didn’t lap up she washed away with her magic, then using the same magic to recover the pair in the bed covers.
“You’re too easy,” Twilight laughed as she lay in bed with her stupor shocked brother, “I think I’ll sleep here tonight. Maybe if you’re a good boy tomorrow and wake me with your tongue, I’ll let you fuck my ass again.”
“Wh-what about when Cadence comes home tomorrow night?” Shining whimpered.
“Well then dear brother, you can go back to boring sex imagining the next time you’ll be inside me” she smiled at the look of guilt on her brother’s face. “In the meantime,” she curled up her wings and leaned back against her brother, “You can give your affections to me.” She looked at him with a sadistic grin, kissing him on the nose before preparing for rest, “If it makes you feel any better, I’ll let you call me Cadence.” Shining blushed profusely as he replied with silence, laying in a nervous, guilty puddle of shame, his beating heart serving as white noise to aid his incestuous mistress off to slumber.