My Stepsister Dresses Like What...?

[IsabellaRose]

His father and step-mother were gone for the entire summer, and Anton had the house to himself. It was going to be a great summer of parties, girls, and anything he wanted to do, as long as he kept it low key enough that the neighbors didn't noticing. But then Mom told him that his stepsister was staying here for the summer. She was supposed to have been with her mother, but now her mother had a new boyfriend and was also traveling most of the summer, and she didn't want his stepsister to be alone for her last summer before college.

Anton had never really liked Aya. Not that he hated her, but ever since their parents got married and she spent every other weekend in his house, it was like living with a hall monitor in human form. She was the type to iron her socks, to color-code her binders, to call "family meetings" over toothpaste caps and who forgot to label the leftovers. She had perfect grades, perfect hair, perfect posture. She never cursed, never broke curfew, never laughed at dirty jokes. And don’t even think about bending the rules at school. Aya Miyazuki, the Class President and Queen of Smug Glances, would have your name written on a report form faster than you could come up with an excuse. She walked like she was always on parade, spoke like a teacher in training, judged like she had a gavel in her school bag.

And Anton? Anton was the step-brother-shaped stain on her otherwise spotless life.

He'd escaped her for his entire first year at college, timing his visits for the weekends she was with her mother, and had only come home because she wasn't supposed to have been there. But then things had changed, and he'd promised his mother that he'd look out for her, despite having zero interest in doing so. Now here he was, stuck with her for an entire summer. What should have been fun had turned into a nightmare of bossy, overstepping, rule enforcing, straight-laced interference.

He was resolved to make the best of it, get his chores done around the house, keep things clean, and spend as little time with her as he could. He had already cleaned the bathroom, emptied the dishwasher and cleaned up after breakfast, and had just finished folding a load of laundry. He had tried to ignore the much more adult bras and panties that she had thrown in with his clothes, folding them without really looking... except for the black lace, the satin fabric, the... no! Sure she'd graduated, she was eighteen, but she was also his stepsister. He wouldn't think about her that way... mostly because he had no chance with her. Not that he'd want a chance anyway. She was so... frustrating.

He picked up the basket and headed for the hall to put his laundry away and leave hers in the basket on her bed. But as he was about to swing her door open, he froze. What the hell was that?

He leaned closer, and he heard it again. It was definitely coming from Aya’s room. 

“Mmn… tail’s in the way…”

Tail?

He knocked lightly. “Aya?”

Silence.

“…I’m coming in to drop your laundry!”

Still no answer. So he nudged the door open... and promptly forgot how to breathe.

There she was. Aya, his stepsister, the girl who quoted the rulebook like it was scripture and once tattled on him for missing curfew. She was currently kneeling in front of her mirror in a skin tight black corset with long gloves, thigh high stockings, clip-on cat ears, a collar with a little bell, a fuzzy tail, and... he could barely process this... paw gloves.

She hadn’t noticed him yet. Her expression was serene, proud even as she struck a pose. Then she saw him in the mirror. Their eyes met. Time stopped.

“...Anton!” she gasped, face draining of color, then flushing violently red.

He took a slow step back. “I... uh... I didn’t see...

“You saw EVERYTHING!!” she yelped, diving behind her bed, only to trip on the tail she’d forgotten was hanging loose and fall with a very undignified thud.

She popped back up, flailing to hide behind a laundry hamper. “You were supposed to knock!!”

“I did knock!”

“You’re supposed to wait longer!!”

He held up the laundry basket, deadpan. “I was just bringing in your laundry and... wait… is that my hoodie you were kneeling on?”

She let out a squeak and kicked it under her bed. “NOPE. Doesn’t even smell like you. Shut up.”

Anton squinted. “Are those… custom fangs?”

“GET OUT!!” she screamed, lobbing a pillow at his head.

He ducked it. “Hey, I’m not judging. Just didn’t realize my stepsister was secretly a cosplay catgirl.”

“You’re not allowed to say those words together!!”

“Too late, sis.”

She froze.

He blinked. “So... this is what the class president does when no one’s home?”

Aya stammered, cheeks flaming. “I... I was just... this is part of a costume... f-for a play... for the summer... drama... club...?”

He raised a brow. “Really. You get dressed up in pet play corsets and crawl on the floor for drama club?”

Her whole body shivered with embarrassment.

“Including the tail plug?”

Silence.

Then a slow, helpless, mortified whimper: “...You weren’t supposed to know what that was.”

They both stood there in the lingering silence.

He crossed the room, arms folded, smug grin growing wider. “Wow. If the school knew their beloved class president was actually a submissive little kitty behind closed doors…”

She grabbed a pillow and hugged it to her chest, trying to hide. “Please don’t tell anyone. I’m begging you.”

Anton crouched next to her, voice smooth and low. “Okay. I won’t tell.”

Her ears perked. “You won’t?”

He nodded, then leaned closer. “On one condition.”

Aya blinked. “What?”

He whispered, “Be my kitty instead.”

Her blush reached nuclear levels. “W-what?!”

“You like being told what to do, right? You like being called a good girl, having someone scratch behind your ears, maybe tug your leash a little—”

“STOP TALKING!!” She tried to bury her face in the pillow.

He tugged the pillow away. “Come on. It’s either I tell Mom why you own four sets of paw gloves… or you sit in my lap and purr like a good kitty.”

“I... I’m not sitting in your... !”

He smirked, pulling out his phone and holding it up, snapping a photo. "I just have to hit send."

Aya stiffened and then, after a beat… slowly lowered herself to her knees again, eyes downcast.

“...Meow,” she said, crawling toward him, rubbing her cheek on his leg.