Just let your sister stay with you! It’ll be fine!

Jessica had known it was a fantasy, but she’d been stupid enough to go along with it anyways. Her dad had been insistent, and her stepmom had gone on this whole rant about taking care of each other. Brittany needed the help, and she was family, and it’s just for a couple months until she’s back on her feet, and Jessica had that guest room, and wasn’t it time that she gave back a little?

In the end, Jessica had agreed with it just to shut them up. That had been a mistake.

Within minutes of getting her step-sister set up in the guest room, Jessica was regretting it. Brittany was blasting music at about a million decibels, completely oblivious to the realities of living with someone else who had ears. She hadn’t changed in the years since Jessica had moved out, clearly.

That was Brittany, though. Momma’s little girl. There was only room for one person in her reality, everyone was there to serve her.

It’d been that way since they were teens, when they’d first moved in together. Brittany always got the extra slack, the extra help, the excuses to cover her bad behavior. If Jessica stayed out a minute later than she was supposed to, she’d get grounded. Brittany could come home at three or four in the morning and get a light scolding.

Despite being a year Jesicca’s senior, she was the baby of the family. Jessica was sick of it.

Knocking on the guest room door, she called, “Brit? The music’s a little loud, could you turn it down? I’m trying to work on my thesis!”

No response. Jessica banged on the door louder. Still nothing. Either Brittany genuinely couldn’t hear her over the pounding of her terrible EDM remixes, or she was pretending not to hear to avoid having to deal with it.

Either way, it meant Jessica had time.

The two-dozen pink padlocks hadn’t been cheap. Jessica had needed many of them to be a unique shape to fit a specific purpose, and they all had the same custom label engraved on the front. While Brittany jumped up and down in her room, being terribly loud and obnoxious, Jessica moved around her apartment, locking things away one at a time.

The fridge and the cupboards first, so Brittany couldn’t just steal food. A plastic case that covered the TV remote, locking away access to any entertainment programming. Another case around the wifi router, just to be sure she didn’t fiddle with it once the password got changed. Jessica’s bedroom door, obviously. Even one to lock the toilet seat in place, rendering the bathroom in the house useless if you didn’t have the key.

Anything that Brittany would try and use without permission got locked away, and on every lock, in big, cutesy letters, it read, ‘FOR BIG GIRLS ONLY’, with a number of stars ranging from one to ten emblazoned on the bottom.

Then, with all that done, Jessica waltzed to the back of the house, humming a tune she could barely hear, opened the electrical panel, found the breaker switch for the guest bedroom, and flipped it.

Finally, she thought, as the music died. Blessed silence.

Then, Brittany screamed. “What the shit?”

Aaaand there’s that obnoxious noise again.

Taking out her phone, Jessica thumbed the command to change her wifi password as she walked back to the bedrooms, cheerfully. Today, things were going to change. Even Brittany might get a change, if she was a good girl.

Slamming open the guest room door, Brittany stormed out of her room. “What the hell, Jess? Didn’t you pay your freakin’ electric bill?”

“Oh, yes,” Jessica smiled, saccharine sweetly, at her step-sister. “I paid the electric bill. You didn’t. And as long as you’re going to be a guest in my house, we’re going to have some changes around here.”

Brittany spluttered. “What?”

She wasn’t used to not getting her way. Jessica savored it. “Here’s the deal. You want to live in my house, rent free? Then you have to do what I say. Anything you want to use, you have to earn it, or pay for it yourself.” Tilting her head, she smirked and added, “But you burned through all the money mommy gave you, and you don’t have a job right now, do you?”

“You bitch!” Brittany said, taking a step forward. “You’re gonna hold that over my head?”

“Not at all. If you want to leave, you’re welcome to. If you want to stay, though, and get the only free roof over your head that you’re likely to get, you’ll shut your mouth and listen for once.”

Brittany stared. For once, she was at a loss for words.

Jessica grinned, holding up her key. “This is the big girl key. From now on, anything you want to do in my house, you’ll need to use this. You want free food? It’s behind this key. You want something to drink besides water? It’s behind this key. You want to use the internet? Take a guess what it’s behind.”

“The key,” Brittany frowned.

“That’s right. And I don’t turn it for free. You want anything, you need to do chores. You know, chores? The things you didn’t have to do as a kid, because you were too much of a free spirit? Yeah, you get to do them now. I’ll get you a list. Every chore you do, you get a star, and every star can open a lock somewhere in this house. I made it simple, so you could follow along.”

“This is ridiculous,” Brittany stammered. “I’ll tell Mom, she’ll make you-”

Jessica had been holding on to her trump card for years. The one bit of leverage she had over her sister, besides a bank account and a mortgage. “If you tell mom, I’ll tell her you sold your grandma’s jewelry to buy pot.”

Brittany’s eyes widened. Realization, and then fear. “You knew about that?”

“Since the day it happened, Brit,” Jessica said. “I’ve got pictures and everything. I don’t know how mom bought that story about a cat burglar to begin with, but if she finds out it was you, you’re cut off. Even you can’t get around that.”

“Then…” Brittany said, blinking. “I’ll… I’ll leave.”

“You’re welcome to,” Jessica smiled. “But I know you. You wouldn’t even ask about staying with me unless you ran out of couches to crash on. You want to stay here, you follow my rules. You break my rules, or you try and get around them by cheating, or you piss on the floor or you annoy me too much, then you’ll either accept your punishment or you’ll move out. I honestly don’t care which you pick.”

She had her step-sister dead to rights, and they both knew it. Brittany had no choice. Jessica knew the wheels were turning in her sister’s head already, trying to find a way around this, to think of a boyfriend she hadn’t worn out her welcome with yet. But for now, she had to admit defeat.

Swallowing her pride, Brittany said, “Okay.”

“Great! If you want the power back on in your room, that’s one star for a day. The wifi password is two stars a day. The chore chart’s on the fridge!”

Brittany hadn’t even found out the best part yet, and already Jessica was giddy. She’d won. After looking over the chore list magnetized to the front of the fridge, Brittany got to work washing the dishes in the sink. Doing chores, working, for what amounted to a paltry allowance.

As she got done, Jessica wandered over, inspecting her work. Half a dozen dishes went back into the sink to be rewashed, and then, as she finished that, Jessica put up a single gold star on the chart.

She could tell from the glares and glowers that Brittany was pissed, but that just made her happier. Revenge was sweet, and cold, like french vanilla ice cream, and Jessica couldn’t get enough of it.

Brittany swept and mopped the kitchen floor, enough to earn two more stars, and with those three unlocked she cashed in to get the electricity and the internet back. Jessica unlocked the breaker box, gave Brittany that day’s wifi password - beagoodgirl - and then sat down at the dining room table to get some work done, and to wait.

There was no pounding music. With luck, Brittany was actually working on her job applications. Each one she sent in was a whole star on the chore chart, and it was the only chore that wasn’t limited to once or twice per day, so it was the best way for her to earn stars, and earn freedom from Jessica’s rules. Even if she wasn’t working on applications, though, that just meant the revenge would last longer.

It took an hour before Brittany shuffled out of her room, anger and frustration clear on her face, and shuffled over to the bathroom. She shut the door, a second passed, and Jessica smiled as she waited for-

“What the FUCK?”

Shutting her laptop, Jessica waltzed to the bathroom, meeting her step-sister at the door. “Is something wrong?”

“You locked the fucking toilet?” Brittany demanded.

“Language,” Jessica chided. “If you swear again, that’s a punishment.”

“The fu-” Brittany started, but she was in Jessica’s expression that it wasn’t a joke. “Why did you lock the freaking toilet?”

“Because, that’s a privilege for big girls,” Jessica snickered. “And an expensive one, at that. Ten stars to use the potty.”

“What do you expect me to do?” Brittany demanded, knees pressed together. She was a little desperate, which just made the thrill of power that much more potent. “I can’t do ten of your stupid chores that fast!”

“Of course, but that’s why there’s an alternative.” Not hiding her giggle, Jessica walked past her step-sister into the bathroom, crouched by the bathroom cupboard, and came out with a disposable diaper and a clear plastic cover. Like everything else in the house, the cover came with a small, pink padlock that had three stars at the top and one at the bottom.

Brittany stared. “No. NO. No fucking way.”

“Then piss your pants, and I’ll make you stand in the corner for ruining my nice hardwood floors,” Jessica replied.

“You’re joking!” Brittany demanded. “You’re going to make me work to put on a diaper?”

“No! Don’t be silly,” Jessica teased. “I’ll put the diaper on you for free. If you want a change, though, you need stars for that.”

Brittany eyed her, warily. “... how many stars?”

“Three stars to change a soggy diaper,” Jessica smiled. “Stinky diapers are just one, because I’m generous like that.” A little incentive to make her step-sister humiliate herself was always nice, too. Either Brittany could burn up stars changing her diapers while they were just wet, or she could wait until she’d made a mess and then get changed so that she’d have stars to pay for food and wifi.

“Fuck off!” Brittany shot. “No way!”

Jessica had her ultimatum ready. “Then piss your pants or go away.”

Brittany danced her weight from foot to foot. She was clearly desperate, and doing the math. She had used all her stars already, so if she accepted this deal, she’d have to get to work if she wanted to be dry anytime soon.

Finally, cheeks burning with humilation and anger, Brittany said, “Fine, I’ll wear the stupid diaper.”

“Great!” Reaching out, Jessica grabbed her big sister’s wrist, pulling her towards the couch. Caught off guard, Brittany stumbled to keep up, until she was pushed down onto the couch surface.

Unsnapping the jeans, Jessica pulled her step-sister’s pants off, along with her panties, tossing both on the floor. “Lift your bottom, baby!” she teased, holding up the diaper and waiting.

“I’m going to kill you for this,” Brittany fumed, obeying, knees trembling as she held it.

Jessica folded up the diaper, pulled the tapes snugly around her step-sister’s waist, and followed the diaper up with the locking plastic cover. With a little ‘click’, the ‘FOR BIG GIRLS ONLY’ padlock snapped shut, trapping Brittany in her first diaper since infancy.

“Now,” Jessica said, grinning. “I think I heard you say some naughty words. Since it’s your first time, I think ten minutes in the corner should be enough to make you learn your lesson, don’t you?”

“I hate you,” Brittany shot back. “I actually hate you.”

“I could always leave you in that diaper forever,” Jessica teased.

The threat wasn’t exactly true - it wouldn’t be hard to remove the cover with scissors, but taking it off without cutting or tearing the plastic would be impossible, which was the point. Not to be impenetrable, but to be tamper-proof.

Still, Brittany hadn’t tested the cover all that much, and Jessica hadn’t lied to her about anything else so far. Blushing, she got up, waddling slightly as she walked to the corner of the room and put her nose in it.

Taking a couple covert photos of her step-sister’s humiliating position, Jessica waited. She could tell, by the uncomfortable shuffle, the attempt at closing her legs that thick padding foiled, and by uncomfortable whimpers, it couldn’t be long.

Sure enough, Brittany lost the fight. With a shudder, she whimpered, and in the quiet Jessica could hear a hissing noise as her step-sisters diaper began to sag.

More photos, and a reminder. “Seven more minutes, crinkle pants, then you can get back to work and maybe earn enough stars to change your soggy bottom.”

Brittany fumed, and Jessica gloated, saving the evidence of her big sister’s accident. A little more ammunition to hold over Brit’s head, should she start getting too big for her crinkly britches.

It looks like their parents had been right. This visit was going to be a lot of fun, after all.