Rarity's Little Secret

by PopsicleLove

Rating: teen
Tags: Slice of Life, Comedy, Random
Length: 1997

Rarity accidentally shows her little sister her love of diapers, Sweetie Bell treats this as an opportunity to treat her sister as a baby.

Rarity has a love for diapers, but it would be unseemly for Ponyville's most esteemed fashion designer to wear such a garment.
Rarity accidentally shows Sweetie Belle her love for diapers, and Sweetie Belle reacts by treating her big sister as a big baby.
In the end, Sweetie Belle just may get her own taste of the cake.

Published 1970-01-01 00:00:00 UTC
Last updated 2015-10-05 19:20:27 UTC

Rarity's Secret

     Rarity smiled. It was a sweet September night, and another successful day at her boutique. She quietly tip toed to her sister's room. Sweetie Belle was quietly snoring, sound asleep. Rarity carefully walked into her room and went into the locked drawer of her dresser.

A most delightful package awaited her, full of comfy diapers. She slipped one on and immediately giggled from delight. She looked at herself in the mirror and smiled. Today was Friday, so the next day would be Saturday. Saturday was when the boutique was closed.

     Rarity carefully buried herself into her blankets on her bed, and her diaper made a quiet crinkling sound. Her horn glowed and her pink frilly night cap flew over to her. She slipped it on.

"Rarity?"

Rarity groaned. It was the sound of her sister. She buried herself under her blankets.

"Rarity? It's noon." Sweetie Belle called outside of her door. Rarity groaned again.

"Five more minutes!" she shouted.

"You promised you'd make me some lunch!" Sweetie Belle whined.

"Five more minutes!" Rarity called again.

"But you promised!"

"I said five more minutes!"

"I'm coming in there!" Sweetie Belle shouted. Rarity jumped up. Her drawer! Her diaper!

"No!" Rarity shouted. "Uh, let me just get changed and brush my mane! Um, bedhead you know."

"Your mane's always perfect." Sweetie Belle said. Rarity's heart melted. Aww!

"Be there in a minute." Rarity said.

"Okay, I'll just get stuff out for lunch. Will you make me an omelette?"

"Yeah sure." Rarity said, re-closing her door. "Just get the eggs and onions ready."

Sweetie Belle headed down the stairs. Rarity sighed.

     She carefully heaved herself out of her bed, trying to stop her diaper from crinkling. Her messy diaper. Rarity sighed. This sometimes happened. Her horn glowed and off it went, she put it in a bag and into her garbage. That would have to do for now.

     She wiped herself carefully. She was all clean now. She put on some powder too. Hmm... maybe just one more minute with a diaper. Rarity opened the drawer a bit more and put on a diaper. Rarity felt the nice snug fit and the texture of it. She let out another quiet giggle.

     Downstairs, Sweetie Belle simply couldn't find the eggs. She heard a quiet giggle from upstairs.

"Rarity?" Sweetie Belle called. She raced up the stairs. Rarity's eyes grew twice in size. Her diaper! Her drawer!

"Wait!" Rarity shouted, but Sweetie Belle had already reached her door.

"I think we're out of..." Sweetie Belle stared in shock. Her sister? In a diaper? "Eggs."

"Sweetie Belle! You musn't tell anyone about this, it simply wouldn't do." Rarity said in a shaky voice. Sweetie Belle's mouth hung open. Rarity managed a nervous smile.

"Um..." she said. Finally, Sweetie Belle caught her voice.

"I gotta tell the Crusaders!" Sweetie Belle shouted, running out again. Rarity's eyes widened again. "NO!"

     She chased her younger sister and blocked the door. "If you tell anyone I swear!"

Sweetie Belle was staring at her diaper again. Rarity let out an exasperated sigh. Sweetie Belle's shocked expression turned into a mischevious grin. Rarity gave her a confused look before realizing what she meant.

"No. I will always be the older sister here. ALWAYS." Rarity said.

"My older sister who wears... diapers!" Sweetie Belle said in her snotty dramatic voice.

"I am not letting you treat me like a foal." Rarity said.

"How'd you know?"

"Sister's intuition."

"I thought it was mother's intoo.. intoo..."

"Anyways! I am not the foal here, you are." Rarity shouted, much loader than she had expected.

"If you let me then I won't tell anyone. And I won't open the door right now." Sweetie Belle said.

"What?" Rarity said in a strained hauty voice.

"I could just open the door. Then everyone would see." Sweetie Belle grinned.

"I- I- I- I.... I just..." Rarity stuttered. Then she lowered her head. "Fine."

     Sweetie Belle grinned wider. As usual, their parents were  gone. This was going to be a fun weekend!

     Rarity sat on a chair with a grumpy expression.

"This is the worst possible thing!" she cried. Then she heard a click. She turned. Sweetie Belle had clipped on her diaper so she couldn't take it off.

"Hmph." Rarity said. Sweetie Belle motioned for her to follow her to Rarity's room.

"You gotta have some baby stuff in here somewhere." Sweetie Belle said.

"Under my bed..." Rarity muttered.

"Why thank you my little sister!" Sweetie Belle laughed. She got out Rarity's baby stuff. "Baby bottle... pacifier... you got everything in here!"

Rarity slouched. Sweetie Belle filled the bottle up with warm milk, per Rarity's instructions.

"If you're going to baby me you may as well do it right!" Rarity had exclaimed. Rarity sulkily sucked on the bottle's nip. A couple minutes later, Rarity whimpered.

"I... I... I have to go." Rarity whimpered. Sweetie Belle grinned again, and then, assuming her most serious, stuck up face she could, she said, "Then go. Nobody's stopping you."

     Rarity had forgotten, if only for a moment. She whimpered. Suddenly, (yelling, "TICKLE MONSTER!") Sweetie Belle tackled her "little" sister with tickles, in her armpits, on her neck and on her belly. Rarity started to laugh hysterically.

"Stop.... it!" Rarity said between giggles. Sweetie Belle stopped. Her tickle attack had only increased her sister's wiggles. Sweetie Belle eyed her sister.

     Sweetie Belle, wanting to humiliate her sister as much as possible, she filled up another bottle and stuck it in her sister's mouth.

"Mmph!" Rarity exclaimed before sucking on it and glaring at her sister. Sweetie Belle gave her a sweet smile and batted her eyes. Rarity rolled her eyes, still squirming. When the bottle finished Rarity let out a big gasp of air.

"Oh my god that was a long time to hold your breath!" Rarity exclaimed. Sweetie Belle rolled her eyes and smiled. Sweetie Belle noticed she had stopped squirming. Rarity followed her sister's gaze to her diaper and realized it was wet.

"Oh dear." she said, embarrassed. "Are you sure you wanna change me?"

"Nope!" Sweetie Belle smiled.

"Oh alright, then shall I get the next diaper from my room?"

Sweetie Belle just gave her another evil smile. Rarity's little smile disappeared faster than you could say her own name.

"I'm not going to stand around in a dirty diaper for the whole day!" Rarity shouted.

"Yes you are!" Sweetie Belle smiled. "Stand."

     Rarity glared, but stood. Sweetie Belle whipped out a camera and snapped a picture just as Rarity's face turned into horror.

"If you rebel then I post all these pictures in the newspaper tomorrow!" she smiled. Sweetie Belle's smile turned into a grin as she saw her sister wet herself a bit more at her words.

     Rarity was really starting to regret her love of diapers. She'd been stuck in a messy diaper for about six hours and since her first wetting, she had peed two more times and went the other one once. She refused to sit. Not only that, but her sister had also fed her apple sauce the whole day aside from baby bottles and she had hand fed her. She almost felt like crying. Instead, she let out a growl.

"Bed time!" Sweetie Belle shouted. Rarity checked the clock.

"It's only seven!" Rarity concluded.

"That's when babies go to sleep." Sweetie Belle sing songed.

"Will you at least change me?" Rarity asked.

"That's the fifth time you've asked me so now my "widdle" sister gets a punishment." Sweetie Belle glared. Rarity glared back. Then, closing her eyes, shouted, "Hmph!"

     She heard her sister go get something. Then she felt her lift open her diaper... and she felt something pour in.

"WHAT IN CELESTIA ARE YOU DOING?" Rarity screamed, looking at Sweetie Belle suddenly, shooting daggers out of her eyes.

"Punishing you!" Sweetie Belle said. Rarity felt something squishy in her diaper.

"What. Did. You. Do?!" Rarity said through clenched teeth. Then she looked underneath herself. Something was sopping.

"Milk!" Sweetie Belle grinned. Rarity glared.

"Hmm... this is fun!" Sweetie Belle said. She snapped yet, another picture and ran down to get something more. Rarity nervously paced, muttering to herself. Sweetie Belle came back. Rarity yelped as she poured cereal down in with the milk.

"Milk always is better with cereal!" Sweetie Belle beamed.

"You're wreaking my coat!" Rarity said, acknowledging her once beautiful white coat underneath her soggy diaper.

"Oh well!" Sweetie Belle said. Rarity whined.

"Hmm... enough whining! That deserves a punishment."

"Doesn't everything?" Rarity moaned. Instead of leaving, however, Sweetie Belle stared, thinking of a suitable punishment. Her eyes lit up like a lightbulb.

"Sit." Sweetie Belle said.

"What? No." Rarity said, thinking of what could happen if she sat with all the contents in her white garment.

"Sit." Sweetie Belle said, clenching her teeth.

"No." Rarity glared. Sweetie Belle glared and snapped another picture. Rarity stood back in shock, and tripped. She landed on her rump.

"Eeeeew!" Sweetie Belle said.

"No kidding..." Rarity said. She stood. Then she started to groan. She had to clean this up later!

     Nevertheless, Sweetie Belle went to fetch adult sized baby pajamas for her sister. She came back quickly and told Rarity to put them on. Rarity obeyed. Then she carefully went to bed on her side, so not to squish the contents of her diaper.

"Need a bed time story?" Sweetie Belle said in a baby voice.

"No thanks." Rarity glared, and put on her sleeping mask. Sweetie Belle snapped another picture. Then she left to go to bed. This mature pony stuff was hard!

     The next day, Sweetie Belle headed downstairs, Rarity still sleeping. What she saw there shell shocked her. Her mom! Her dad! And... Rarity!

"I thought you were sleeping!" Sweetie Belle exclaimed to Rarity. She noticed her rump was bare, but quite dirty.

"We are very disappointed in you Sweetie Belle." said her mother. Sweetie Belle gave her best big eyed, teary guilty look to her mum.

"You knew that she loved diapers?"

"Yes." said both her parents. "She's always been like this. And you should be ashamed of yourself to take advantage of that."

Sweetie Belle gave up her attempt to guilt trip her parents and hung her head.

"We've decided you must be punished." said her father.

"But wait, why are you home so early?" Sweetie Belle asked.

"Our work was done early." said her father.

"Oh..." said Sweetie Belle.

"Your punishment will be first off, cleaning the mess you made of your sister's coat." said her father.

"And second off, you will be taped into diapers for the whole week, inside the house, outside the house, daytime, night time, 24/7." Sweetie Belle's mother added on.

"WHAT?!" Sweetie Belle shouted. "But that's not fair! I only had Rarity in them for a day!"

"But you also took advantage of your sister and black mailed her. You also embarrassed her intentionally." said her father. Sweetie Belle hung her head. Rarity stepped up.

"Come here." she said. Sweetie Belle came. "Lie down."

Sweetie Belle obeyed once again. Rarity strapped on another, clean, diaper onto her sister.

"And now you should wash your sister's coat." said Rarity and Sweetie Belle's mother. Sweetie Belle nodded sulkily.

"I'm impressed." Rarity said while Sweetie Belle cleaned her coat.

"Why..." Sweetie Belle asked.

"You're taking your punishment quite well." Rarity said.

"Well... what I did was really, really, REALLY wrong." she answered. Rarity nodded.

"Well, you know. After your punishment is over, we'll go to the pier and get ice cream." Rarity said. "I know it's not much but..."

"Oh that'll be really, really, REALLY fun!" Sweetie Belle exclaimed. "And can I bring the crusaders?"

Rarity laughed. "Yes."

"Oh, if I weren't cleaning your rump right now I'd hug you!" Sweetie Belle exclaimed. Rarity laughed again, and embraced her sister.