Half Sister, Half Wife

by Prettypony

Rating: mature
Tags: Princess Cadance, Fetish, Comedy, Shining Armor, Sex, Twilight Sparkle, Profanity, My Little Pony: Friendship is Magic, Romance
Length: 5973

Shining Armor asks Cadance if he can do incest with her. Sex happens

My entry for Shakespearicles' Hearts and Hooves Day Contest.

Shining Armor is a dork who doesn't always think logically. When Cadance asks him what he wants to do most for their anniversary/Hearts and Hooves day, he tells her he wants to make sweet sweet incest with her. She incests him.

Contains: Attempts at humor, sex, incest, spit, magic, spike.

Special thanks to my friends for editing and prereading. Especially tailsopony, your editing helped a lot.

"it's like watching a baby learn to walk"

—Majin Syeekoh

Published 2024-02-12 20:20:00 UTC
Last updated 2024-02-12 20:20:00 UTC

When you've got magic

Cadance soon found herself back at home. Armed with a copy of the ancient tome and a freshly stamped book card, she spent much of her time studying the texts and practicing forming the spell matrix. Shiny would be home soon and she wanted everything to be ready to go for him.

Sure enough, he came. “Hey, you’re back! Did you get everything you needed?”

She nuzzled his cheek. “Sure did! The spell itself isn’t too hard to cast, it just needs more setup than others do.” She presented the tome to him, the relevant pages already selected in her magic. “See, pretty simple matrix compared to what it’ll do.”

Shining studied the spell, humming to himself as he did. “Huh, must be because of the—” He squinted at the page, “—material components?”

Sensing his confusion, Cadance revealed the ‘specimens’ her sister-in-law gave her. “Twilight said, ‘the more the better.’ But since I don’t know anypony who’s related to me, I’ll just have to use more of my own ‘genetic material’ for your half of the spell.”

Shining nodded and hugged his wife. “You’re really sweet for doing all this, you know that?”

Cadance hugged back. “Anything for you, sweetie.”

Shining held her tighter for a moment before letting go. “I’m ready when you are.”

She nodded. “Right, we just need to gather our own ‘samples’.”

Cadance sat across from her husband. They stared intently into each other's eyes. The tension in the air was palpable as they knew what had to be done and what it would lead to. Cadance broke first. Her stoic mask faltered as her maw turned upwards. She giggled, silently at first, then more audibly as she spread her contagious joy. “Shin–hahahah–Shining! Hee hee! Oh, what are we doing?”

Shining, never one to let a good sex mood go to waste, fed fuel to the fire. “I believe we were just about to jerk off into some jars so we can do some incesting.”

Cadance’s laughter grew louder and more joyous. “Haha! Really Shiny? Incesting? I know I’m not good at dirty talk either, but that was bad.”

Blushing, Shining Armor started to tease his cock out of his sheath. “Hah, yeah you’re right, but it’s your turn now! Give it your best shot.”

Growing wetter by the second, Cadance began rubbing at her snatch at a leisurely pace. Getting herself nice and warmed up as she watched her husband’s cock grow and grow. “Oh Mister Prince Armor,” She started in an overly sultry tone, “won’t you help me? I have to collect all of these samples so that I can become genetically related to you.”

Shining stifled some giggles, his body gently shook as he tried to maintain control of himself. “Oh yeah?” He replied in an equally exaggerated tone, “Why should I do something like that?”

Throwing back her head and pulling her hair back in a way that would make even a novice actor cringe, she said, “Oh it’s just terrible! I just don’t want to have kids unless they’re incest babies! Am I wrong for wanting something that’s done by like, twenty to thirty percent of equestrians and isn’t really a big deal?”

Shining laughed again, but it was tinged with a sense of awkwardness and fear. “I don’t really sound like that… Do I?”

Cadance stopped her rubbing and crawled over to her husband, bringing her collection jars with her. “Sorry about that. That might have been a little mean.” She kissed him on the cheek. “I shouldn’t poke fun at your insecurities.”

He kissed her back and brought her into an embrace. “It’s ok, I know I can get a little, uh, competitive, when I play O&O.”

Grinning like a Cheshire cat, Cadance whispered, “I’ll give you a big ‘O’.”

Shining snorted, and the two enjoyed the simple joy of the other’s presence. That was, until they noticed they were both starting to ‘cool down’ despite not having completed their mission.

“Uh oh, looks like Shining Junior is falling asleep!” Cadance said, “Guess that means we won’t do some incestin’ after all.” She pouted for added effect. “Unless…”

“Go on…”

Cadance clopped her two hooves together. “Unless I could, perhaps, give you a little help?” She looked desperately at Shining. “Haha! Oh, just kidding!” She said in a much more nervous tone. Her eyes darted up to him again in a pleading expression. “Unless…”

Shining burst into a giggle fit, his half mast cock flopped around with him. “Oh! Oh! Noooo! You can’t just apologize for poking fun at me, only to viciously mock high–school–me! Haha!” He shared more laughs with his wife until they both settled down. “Oh, my sweet dear, sweet dear precious baby girl darling sweet precious dear girl Cadance, I shall allow you to ‘warm me up’, as the commoners say.”

Bumping his shoulder, Cadance couldn’t help but snort. “Oh thank you milord! How gracious of thee to allow this lowly alicorn the honor of raising yine owne flageth poleth!” Visible spittle was produced as she exaggerated her fake Olde Equestrian accent.

Shining nodded. “Indubitably.”

Cadance grabbed his cock and started working her hoof up and down in slow pumps. “Quite.”

“Hmm mhm. Yes.” His cock slowly stiffened.

“Ahem harumph! Harumph, yes!”

Shining, noticing that his cock was now fully erect, smacked his wife’s hoof away. Though, not hard enough that it would actually hurt. “Enough! I shalt taketh this into mine owne hoofseths now, lest ye contaminate mine sampleth!”

“Oh! You’re right, you’re right! I shall churneth the buttereth of mineth owneth sampleseths!” Cadance scooted a few inches away so she could get back to her own pussy. Unlike with Shining, her snatch had only gotten wetter from all of their dirty talk.

Within minutes, the two of them had gone from ‘warming up’ to actually masturbating. Cadance teased her clit with one hoof while the other ventured gently inside her. Shining was pumping his hoof up and down his cock when Cadance turned towards him. “Like what you see? Just think, in less than an hour, we’ll do allllll of the incesting you could ever wish for.”

Shining pumped faster. “Mmm, I’m gonna knock you up.”

“With an incest foal?”

He nodded. “Oh yeah, gonna creampie you so hard once we’re both genetically related and uh…” He trailed off, looking for an appropriate end to his sentence. “Uh, stuff. Yeah.”

Cadance worked herself more. “Yup, we’re gonna do so much incest and stuff. Just like, soooooo much stuff. You don’t even know how much stuff we’re gonna do.”

“Oh? I don’t?”

“Yeah, you don’t. Once you knock me up with an incest baby, I’m gonna send a nice little letter to Twilight asking her if she’d like to join us.”

White fur turned red as he processed the statement. “Does she even know I’m into that? What if she gets the wrong idea?” He asked in a panic, rubbing harder and faster as the scarousal hit him.

“It’s kinda hard to go up to somepony you haven’t seen in over a year just to ask, ‘Hey, can you teach me a spell to do this really complex and specific thing with no questions asked?’" She outstretched a wing to hold his withers. "Don’t worry, she’s totally into it.”

Shining nodded. “It is pretty hot though. Even if it’s kinda weird because she’s my sister.”

Cadance stopped everything and shot a pointed look at him.

He threw up his hooves. “Hey, I didn’t say it wasn’t hot! Because it is; it’s just weird because I’ve never really thought about it. So it feels new, and new feels weird.”

Kissing him, Cadance giggled and whispered to him, “I’m getting close. Want to finish together?”

Shining kissed back. “Absolutely.”

Together, they worked faster, both of them recognizing each other's signs and using them to go further. At the last second, Cadance used her magic to hold the jars in place, catching both her and her husband’s cum.

Panting and feeling a strangely nice afterglow given the circumstance, they embraced and spent the next few minutes cuddling and canoodling.

Having emptied their specimens in the collection jars, they gathered them together and began casting. Cadance, having studied the spell more, began the casting. Shining joined her, using his magic to fill in the gaps as well as to connect himself to the spell. A silver light filled the space between them. It first colored the room, then formed a solid sphere of light between the two of them. Tendrils grew from the sphere, each one reaching down to a different dish. They blindly searched for the samples until they brushed up against one. Once the tentacles identified their target, they quickly grabbed it and pulled it into the central mass. As for the fluid samples, the tendrils simply drank them up like long proboscides.

The sphere grew with each sample it absorbed. Once the sphere consumed the last of the samples and had grown to maximum size, it quivered once, then exploded. Tendrils erupting from it shot along Cadance and Shining's magic trails. They rapidly reached the two, encasing them in silver shells of light as they rose into the air. The magic energy then coalesced, all tendrils not connected to Shining Armor and Cadance rejoined the central mass. Which was starting to pump more of its light into the streams connecting it to the two until it was simply one thick cord of light between them.

The light bridge pulsed and smaller lights ran along its length between them, as if the spell was transferring information between them. Streaks of light shot to both of them, though slightly more came to Cadance. She felt a growing warmth starting in her hooves and then spreading throughout her torso. The pleasant burning sensation consumed her and she didn’t feel anything else until her hooves bumped into the ground again.

She looked up to find her husband lowering to the ground as well. She gasped once the light faded and got her first unblemished view of him. “Shining, your fur is pink!”

Shining quickly came to his senses and examined his fur, finding that it was indeed pink by comparison to the pure white his fur once was. Examining it closer, it was still mostly white, but many numerous pink strands of fur now grew alongside the others, giving his fur a pinker appearance. He looked up only to realize his wife had a similar transformation, her fur now lighter in hue. “Speak for yourself.” He said, pointing at her.

Cadance looked down at herself, gasping once at her fur, and then again when she looked at her hooves. “I have feathers!” She held up a hoof, playing with the mostly-white fluffy fur which now grew in abundance from her fetlocks.

Shining nuzzled her. “Dear, you have wings.”

Cadance snorted. “You know what I meant, Captain Ding Dong.”

“Speaking of ding dongs, my peepee is hankering for a right good romp in your hooha if you don’t mind me saying so.”

Snickering, Cadance pushed him away. “That was your worst one yet.”

He dusted off his chest. “I aim to impress.”

Cadance pulled him into a kiss. Starting as simple smooching and progressing into a panting, open-mouthed, tongue wrestling match. Shining ‘won’ the match, although neither of them would count being the non dominant partner as ‘losing’.

Breaking away from the kiss, Shiny stood and looked down at his breathless wife. With a single hoof, he pulled her up by the chin and she followed, making her feel weightless in his grasp. He led her onto the bed and climbed on top of her. She moved her forelegs above her head and Shining pinned them down with one hoof. Using the other to caress his wife, he squeezed her cheek.

She gazed up at him with stars in her eyes. “Wow… Wow. You are really getting into this now.”

He gave her a tender smile. “It’s hard not to when I have such an amazing, beautiful, smart, kind wife. You do so much for me and I’m the luckiest stallion in the world for it. I love you, Cadance.”

Cadance’s heart swelled in her chest, the very one Shiny was caressing at the moment. “Awww! It’s hard not to want to indulge you when you are one of the sweetest, most thoughtful, and funny stallions I know. There isn’t a day that goes by where I don’t count myself lucky to be married to you. I love you too, Shiny.”

Shining smiled, warmly at first, then twisting into a more lascivious grin as he pulled his wife’s mouth open. She brought out her tongue, knowing what was about to happen as Shiny began to spit. Not a short violent action, like how one might use a spittoon. But a slow pooling of spit at his lips that slowly drooled down. More and more bubbled and drooped down the string between them and as it finally connected, Shiny finally let it drop fully into her mouth with a ptu!

Swallowing eagerly, she opened her mouth again only for him to do the same thing. They repeated that for a while, some spits being long and drawn out, while others were short and quick.

It was only the slapping of Shining’s cock against his belly that broke them from this routine. Caressing her cheek, Shining asked her one simple question, “Are you ready to get pregnant?”

It took a moment for her to gather herself, but when she did, Cadance looked into his eyes with love and adoration. “With you? Always.”

Shining smiled, bringing her into another deep kiss as he lined himself up with her pussy. She moaned into him when his cock tip pressed into her. He broke the kiss and dragged his tongue up along her face, starting from her chin and working his way up her horn. She moaned and squeaked as he licked each of her sensitive spots while he took his time rubbing his cock against her entrance.

With a nibble of her cheeks, Shining pushed himself in and earned a delightful symphony of whimpers for it.

Cadance was into pretty much everything, and while the new incestuous nature of their relationship elevated the experience, nothing could outshine her love for her husband. Every inch he took forward delighted her more than any physical sensations could, though, the bliss he inflicted on her was pretty darn good too.

Shining wasn’t done with her either. He cast two spells in quick succession before she could even think. Her brain froze as she felt something penetrate her now thoroughly lubed rear while at the same time Shining’s magic vibrated against her winking clit.

Squealing, Cadance arched her back, her movements being stifled as Shiny’s magic pinned her wings down to the bed. The best she could do was clamp down on him with each thrust out, though her body was doing that on its own. She tried lighting her horn but was quickly stopped.

“Ah ah. You’ve done so much for me already. Let me do the rest of the work.”

Looking up at the veritable stud inside her, the way his muscles flexed and moved with his thrusting, Cadance knew she wouldn’t last long. In one last attempt to give as good as she was getting, she softly yelled “Sh-Shiny! I’m going to cum!”

Nostrils flaring, visible steam shot from them as his thrusting picked up rapidly. His achilles heel having been exploited, he rutted her like a feral beast as he knew he wouldn’t last much longer. Pre cum started bubbling out of his shaft, oozing out in thicker and thicker jets as he flared painfully. His every instinct yelling, screaming at him to cum with his wife.

“Agh! Nnnng, fuck!” He bit down on the scruff of her neck as he pounded her with a last few desperate, powerful thrusts.

Cadance screamed, “Shiny! Shiny! Breed meeeeee!” Her voice wavered as powerful shots of white hot cum blasted into her eager womb.

He came and he came, another cupful of jizz flowing into her with every grunt and groan. He didn’t begin to stop until his wife’s belly was poking against his. With a final spurt, he pulled out of her and used his magic once more before falling with a flump next to her.

They both lay there panting like dogs, too tired to care about the sweat they’d eventually have to wash off. Cadance only realized what spell Shining used when she noticed a lack of the distinct feeling of cum drooling from her snatch. She gave an experimental poke of her belly, confirming her suspicions when nothing changed.

Kissing him once more, she said in a low voice, “You horny dog, there’s no way I won’t get pregnant from this.”

He replied in between pants, “That huff was the best whew sex we’ve had since our honeymoon. I wish I’d told huff you sooner.”

Pulling him closer, she hugged him like a teddy bear. “Don’t worry about that now. Just think about how great everything is going to be going forward.” She paused for a moment, letting him think about that before she continued, “Especially how good things will be when I’m gravid. Do you think Twilight would want a foal?”

Shining blushed furiously, “I don’t know if I should regret all this or if I should thank my lucky stars that it happened.” The two fell into a comfortable silence as they lay in bed. Thanks to Cadance, their relationship had never been stronger. Speaking of relationships, Shining was wondering something. “Hey sweetie, I know I was too horny to ask once I saw the spell and everything, but what exactly is our blood relation now?”

“Hmm. It’ll take a doctor to confirm it, but I’d say half-sister.”

“Wow.”

“Yeah. Half sister, half wife.”

Who needs family?

Cadance lay with her husband in their bed in the Crystal Palace. She turned over to him, and whispered sweet nothings into his ear. “So, Mister Sir Knight Prince Consort You, Hearts and Hooves Day is coming up and so is our special day.” She whispered conspiratorially, “Almost as if we did that on purpose.” The two let out a short chuckle before she added, “I want to make things special. If there was one thing that you could do with me, no matter how crazy or impossible, what would you want to do?”

Shining Armor blushed. “Well, we’ve done nearly everything that I like already.”

“Mhm, ‘nearly everything’ is not everything! You know, and I know, that there’s something you’re too scared to share.” She caressed his cheek and continued in a sultry tone, “You’ve got a princess willing to do whatever you want, you sure you want to miss that opportunity?”

Shiny snorted. “Heh, you say that as if you wouldn’t do this for me any other day of the year if I asked.”

Cadance rolled her eyes. “I’m trying to sexy talk, you dork. Do I need to roll for seduction or something? What’s your AC?”

Putting on an air of playful arrogance, Sir Shining Armor proclaimed loudly, “Twenty. You will never seduce my reverend doctor paladin Lord Edgeskull of Thundercrack Mountain. His virginity is eternal!” His body lightly shook as Cadance laughed into his side.

“You dork.” She kissed him and he soon reciprocated, the two passionately, yet lightly, kissing in each other's embrace.

Cadance ended the kiss, pulling her head back and brushing some of her mane out of her face with a wing. “Still, are you really so afraid of telling me what this deep dark mystery fantasy of yours is?” An undertone of hurt edged its way in despite her best efforts to keep it out. “I thought we could tell each other anything.”

Shining looked down, as uncomfortable as it is to reveal a secret it was worse hearing the hurt in his wife’s voice. “It’s not that it’s dark or anything, it’s just embarrassing…” He tapped his hooves together. “I- I’m really into incest. Like, just so much.”

Cadance raised her eyebrows slightly and clicked her tongue. “Huh. Well… That’s not what I expected, honestly. I was afraid you’d want to invite Chrysalis for a threesome with how much you were repressing yourself.” She watched as her husband went through a gamut of expressions, settling on disgust.

“Gross. Maybe a different Changeling, but her? No.” He looked at Cadance now with the same spark in his eye he always had when he was about to nerd out. “So, you really aren’t put off by the incest thing?”

“Nope! Tell me more, mister.” She lightly played with the fur on his belly as that spark slowly grew into a grin.

“Well since you asked, since I met you, I’ve always thought it would be hot if we were related. Like, incest with you would be really really…” He trailed off, searching for the right word to perfectly encapsulate the totality of his feelings. “Cool. It’d be super cool.”

Static filled her mind as Cadance’s face went blank. “What?”

“Yeah, like, imagine how hot and cool it would be if we had an incest baby!”

“What?”

Shining continued, “It would be incredible because that is just the hottest thing.”

“Hold on,” Cadance started, “is this why we don’t… Why you didn’t… Is this why you’ve put off having kids? Because you, you…” She looked at him with the same disbelief she’d have if he told her he burnt the breakfast cereal. “You want them to be incest babies?”

Shiny nodded rapidly. “Uh huh, uh huh! Yeah yeah yeah!”

An involuntary snort left Cadance as she processed everything. “Wait, if you’re this into incest, why did you date me? Wouldn’t your sister be the better choice, cause, you know, she’s actually related to you?” She looked at him with a bemused grin.

Shining, for his part, spaced out for a few seconds, uttering nothing more than a simple “Huh.” before looking back at his wife. “You know, I never thought about it.”

Cadance was incredulous. “You never thought about it?”

“Never.”

“Never thought about it?”

“Nope, never crossed my mind.”

“Did you even think about your mom, dad, cousins, or anyone?”

Shiny scratched his chin. “You know, I think I’m distantly related to Celestia in some way. Lineage and all that. And I did have a foalhood crush on her. But I don’t think it’d be incest if anything ever happened that way?”

Giggling, Cadance poked him in the ribs. “Heehee! Oh my knight in shining armor, where would I ever be without you by my side?”

“You’d be painting miniatures all by your lonesome in a big castle and shipping your friends, sometimes literally.”

“Hey! It’s not my fault Thunderhead is an idiot! I thought he’d get a train ticket like everyone else, not stuff himself in a packing crate!”

“At least it worked out for him.”

“Yeah, he’d have probably mailed himself back home if Flower Cart didn’t take the train back with him.” She snorted and giggled at the thought.

With Shining now feeling much more at ease, he pulled Cadance closer to him, enough for his sheath to poke her in the belly. “So, do you think you could do it? I’d love to be genetically related to you and then impregnate you.”

“Oh Shiny, through magic, all things are possible. But I don’t know how I’d even get started with a spell like that. Are you sure you don’t want to invite your sister or your parents for a night of fun? It’d be much easier.”

Shining bit his lip. “Hmmm. Let’s save that for after I give you an incest baby.”

Cadance chuckled. “Never change Shiny, never change.” She rubbed his sheath, “In the meantime, how about we do something else?”

[sex happens]

Cadance arrived at Twilight’s humble abode, a gigantic crystal tree castle with Twilight’s cutie mark recreated at the top. Marveling at the thing, she admired the way it bathed the surrounding environment in soft purple light. She could get used to the pony-made castles all she liked, but she’d never get tired of something so beautiful that formed naturally. That was, until a cloud parted and allowed direct sunlight to reach it. Turning the natural wonder into an instrument of death as it focused the unmatched power of the sun directly at Cadance’s wings.

“Yowch!” She yelped as she shot a bolt of light at the source of her pain. The bolt harmlessly refracted through the crystal cutie mark as it continued to fire a death ray at the ground. The statue stopped once the sun moved another degree and the area was once more cast in a calming lavender light.

Scowling, she removed the ruined feathers as she continued on her way. “I should tell Twilight about that.” Not paying attention to her surroundings, at least, not the ones shorter than her knees, she bumped into Spike in the foyer and knocked him and the stuff he was carrying onto the floor. “Oops, sorry Spike!”

“Ow,” He rubbed his butt and then lit up as he realized who he bumped into. “Gasp! Cadance!” He hugged her as quickly as he finished talking.

“Hey Spike,” She said, rubbing his spines as he snuggled into her leg. “It's been a while hasn’t it?

He pulled himself away from the hug. “So why are you here anyway? You didn’t even send a letter.”

“That’s because I didn’t want a big fuss to be raised. I just need Twilight’s help for something private and I’d appreciate it if you kept this quiet.”

“Uh, sure. She’s in the library.” He said as he picked up a lawn chair and shades from the ground.

“Thank you Spike, we’ll have to add ‘Keeper of Secrets’ and ‘Finder of Twilights’ to your official list of titles in the empire.”

Spike flexed a scrawny arm and in a macho voice said, “Don’t worry, Princess. It’s nothing for the hero of the Crystal Empire.”

They both laughed and Cadance said, “Oh, thanks Spike. I’ll have to come by with Shining sometime for an actual visit. See you later!”

He waved as she continued on her way. “Bye!”

She made it soon enough into Twilight’s unofficial second bedroom. Looking around didn't reveal much, just an orange mare in the background. Breaking the quiet, she called out, “Yoohoo! Twilight?”

“Shhh!” Seconds passed in silence until a distant voice asked, “Cadance?” A purple head peeked over a shelf. Twilight gasped as she saw her and quickly flew over the shelf and dive bombed into a tackle-hug. “Oh my gosh! It’s been forever! How are you? How’s Shiny? How’s the empire?” She asked in a frenzy.

Cadance laughed as best she could, having had the wind knocked out of her just seconds before. “Geeze Twilight, you gotta be careful, you’re stronger than you think.” Twilight wilted at that. “Although, I mayyyy have done the same thing to Shiny when he finished his Guard Initiation Training.” The pair laughed at that as they both resettled themselves.

“Now, I know you’ve got questions, but first things first.” Cadance’s horn lit up with baby blue magic as she locked the door to the library. Her horn grew brighter as she then poured more power into a privacy spell which manifested as a sphere of light expanding from the tip of her horn until it reached the confines of the room. Every surface of the room sparkled for a few seconds before the spell faded and everything appeared normal again.

Twilight raised a brow. “Is everything ok? You’re starting to concern me.”

Cadance waved a hoof. “Don’t worry, it’s nothing world ending. It’s just…” She leaned close to Twilight, “Well, it’s private.”

Letting out a breath she didn’t realize she was holding, Twilight said, “Whew, I was worried Sombra was back for a… How many times has he resurrected by now, three or four?”

Chuckling, Cadance replied, “Too many to count. But that’s not why I’m here. Shiny… Well, Shiny wants something that I can’t provide and I need your help.”

Twilight quirked her brow again. “What could he want that only I can give him?”

“First, Pinkie promise that you won’t tell anypony what I’m about to tell you.”

“Cross my heart, hope to fly, stick a cupcake in my eye.” Twilight said, acting out each motion as she did.

Cadance smiled. “So, Shining Armor, my wonderful amazing husband, wants to do incest. That’s why I need you.”

Twilight heard the words Cadance was saying, she knew what each one meant on their own, but it took a few seconds for what she said to register. As the gears turned in her head, her cheeks grew redder and redder. “You’re not—Are you asking me to… I-I never considered—” She was cut off by a laughing Cadance putting her hoof up to her mouth.

“Ohhh Twilight! No, no. He specifically wants to have an incest baby with me.”

Though she stopped her stuttering, Twilight’s blush remained strong. “So, how does he think that’s going to work? If he wants incest, shouldn’t he want to do it with, well, his family?”

Cadance rolled her eyes playfully. “Apparently he ‘never considered it’.” She said, using her hooves for air quotes.

“How?”

“That’s what I said! But what he wants is for me to cast a spell that’d make us genetically related to each other.”

Twilight thought for a few seconds, humming to herself as she did. “Oh!” Her face lit up and a twinkle shone in her eyes. “Oh I know just the spell for that!”

Cadance grinned. “That’s why you’re my favorite sister-in-law.”

She gave Cadance a deadpan stare. “I’m your only sister-in-law.”

To which Cadance booped her on the snoot and said in a sing-song voice, “Still counts!”

Twilight rubbed her cheek, eyes gleaming again as she recalled the spell. “So about the spell. It hasn’t been in use for centuries, but I remember it was used to help incentivize adoptions. Ponies back then were more uptight about having ‘blood relatives’, so the spell would be used to ‘adopt’ a pony into a bloodline.”

“That sounds promising.” Cadance said, grinning.

“Oh but that’s not the best part!” Twilight said as she practically lit up the room. “It uses material components! I never get to cast those! This will be so much fun! Eeeee!”

“Huh. That explains why I didn’t learn about it from Celestia. Material spells are pretty old-fashioned.”

Twilight bounced and stomped her hooves. “I know! Isn’t that cool?!”

Cadance chuckled to herself. “Yeah, I guess it is pretty cool. So what do we need and how do we do it?”

“Well, as far as material spells go, this one is pretty simple on the components. You just need some donor genetic material from the ponies involved.”

Cadance had a conspiratorial look in her eye as she brushed up against Twilight’s side and said, “You know, I think Shiny left some ‘genetic material’ in me last night. Wanna get it out of me?”

The result was instantaneous, Twilight’s dimming blush returned with a fury as she stammered and looked for a response. “I, you, that’s—” She stopped once she saw Cadance laughing again. “You tease! That was mean you know!”

Cadance wiped a tear from her eye. “Haha! Oh sorry Twilight, but you’re just too precious. I couldn’t help myself after I saw how you got from learning about Shiny’s kink.”

Twilight snorted, trying to look angry as her own face betrayed her with a smile that fought its way onto her face. “Regardless, the spell works better with the more material you have.” She plucked a few loose strands from her mane, as well as some loose feathers for good measure. “Here, hold these.” She levitated them to Cadance, who picked them out of the air with her wings. She beckoned to her. “Okay, follow me.”

Following, Cadance was led to a locked desk drawer. Twilight produced a key from thin air and unlocked it, revealing a detailed collection of genetic samples from her family, including some from Twilight herself. Most of it was strands of hair, taped to the drawer and labeled with museum tags. There were also labeled jars containing hoof shavings and horn filings. Pulling out a few strands of hair from her parents, Twilight gave them to a horrified Cadance.

“There we go! When you do your part of the spell, these will make you related to us.”

“Twilight… How, how did you get these?”

“I asked. How else would I get them?” Twilight said simply.

Cadance chuckled nervously. “Well, I know how obsessive you can get. I thought maybe you took them from ponies while they were sleeping.”

Laughing, Twilight fixed Cadance with an uncomfortably long stare. “Hah, no. I only do that to the ponies who resist.”

A shiver ran up Cadance’s spine at that, relieved that she knew Twilight was only joking. Hopefully, anyway. “You know, I’m glad you aren’t a dark wizard.”

Rolling her eyes, Twilight said, “Seriously, it’s just a little hair and some shavings. I don’t see what’s got your bridle in a bunch.”

Cadance laughed. “You’re right, it could be worse. I’m just glad you aren’t keeping urine samples.”

Twilight laughed with her, albeit more nervously. She brushed against Cadance’s side and started leading her to the door. “Ha ha! Yeah! Anyway! How about you go to my study and wait for me, I just need to grab the tome the spell is in.”

As they were walking to the door, they were stopped dead in their tracks by a sudden clamor as what sounded like a filing cabinet, glass jars, and a surprised earth pony all falling at once out of view.

“Consarn it! Twilight!”

“Uh oh, I better go deal with that!” Twilight said, suddenly pushing Cadance out of the door with her magic and hooves and slamming it before she could react.

She’d just gotten the door closed behind her as a sopping wet Applejack marched up to her. Slop, fwich, slop, each step was punctuated with a dull wet sound as she stopped inches from Twilight’s muzzle. “Yer shelves ain’t up to code.”

Twilight laughed anxiously, “Haha, yeah! Sorry about that!” She glanced around, looking for an escape.

“Now, I ain’t mad about the cabinet fallin’ on me. That’s my own fault fer tryin’ to climb it without a ladder. I won't say nothing about you wantin' to buck yer brother neither."

Twilight's eyes bugged out of her skull. "You heard all of that?" She said softly.

AJ nodded, "Yup, hard not to when you don't bother making sure yer alone. But like I said, don't worry none. I know when private should be kept private."

Twilight relaxed at that. At least, she did until Applejack suddenly narrowed her eyes on her. “Now, speaking of privacy: Why was there a jar with my name on it?”

POP!

She never got her answer as Twilight teleported her away, and only her. The fluids splashed harmlessly down to the ground. She took one look around the corner and grimaced. Spike could take care of it, she decided.

POP!

She teleported to her study as a formerly sunbathing dragon appeared in her place.

Author's Note

The "[sex happens]" bit was a suggestion from Majin. It was originally just a note to self that I was going to remove, but he thought it'd be funny if I left it in. Said it reminded him of a story he wrote.

I was very much on the fence about keeping it as a joke vs cutting it. Let me know in the comments what you think.