Yeah, I've experienced similar things in the mental hospital. I was put in a unit when 12, and my body was invalidated. A lot. Not sexually, but in other ways, I prefer not to talk about because it normally triggers some sort of panic attack. There was lots of restraining involved. I still can't sleep on soft surfaces, or even sit on them sometimes, because I was restrained on a bed and other soft surfaces. I'm pretty sure they overused restrained on me, they happened several times a week, sometimes multiple times a day.
But yeah. I feel you. Restraints are some really nasty things, and I'm so sorry you had to deal with them.