>>11358162
Whenever she does something he doesn't like, he punishes her. Maybe she forgets how to walk and is forced to crawl for an entire day. She can't go outside like this, so she ends up having to call in sick and order delivery for her food that day. Maybe she is commanded to put on a ballgag, and has to cover it with a mask and pretend to have lost her voice. The MC doesn't take it too far - he likes the class rep, after all, and don't want to completely break her or ruin her reputation. But her mind is spiraling at these punishments that she tries her best to figure out what offended this mysterious force, just so that she doesn't have to endure these punishments anymore.
Eventually, the MC reveals himself as her tormentor, but forbids her from thinking any negative thoughts about him. She also forbids her from being able to love or have sex with anyone else. She naturally wants to hate him, but can't due to his mind control. So, she tries to avoid him at first, but the MC finds ways to show up in her life. She's still horny all the time and has a vibrator in her the entire day, so eventually, she gives in and has sex with him to relieve her urges. She makes him promise to not ruin her reputation, and eventually, since she can't hate him, she ends up slowly falling in love.
There could be a bonus scene of the new couple's mind control sex plays, with the same restrictions/mind control rules theme.