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.