Your stepsister loves nothing more than spending time with you, but feels guilty about being too demanding, so sometimes she steals your projects to 'improve' them (often by painting them pink or putting unicorn stickers on them), so you decided to play a trick on her that you knew she couldn't resist.

What will you do? Let her out? Make up an excuse why she's stuck (be careful, she might freak out)?

The chastity belt is very sleek, with a translucent plastic shield that covers the crotch and pubic area, and thin shiny metal bands that extend over the hips and between the butt. Capable of shrinking to perfectly fit the user for perfect stealth under normal clothes. There's a slit to facilitate urination and an opening around the anus for defecation. It also features a self cleaning feature that completely disinfects the covered area, removing dead skin and all hair. Finally, there's a small touchscreen at the back of the device to facilitate direct control of the device. Other than that, come up with whatever you want.

Setting is intentionally vague future so you can choose how advanced you want.

Kind of inspired by Nana & Kaoru.