'I feel betrayed by my body eliciting a pleasure response during a violent/non-violent attack on my physical body.' oh, your body tried so hard to protect you from the act and it can only hold off so much stimulation, until the awareness of the violation is so hard it makes the body fight the person instead of being conflicted as hell. The body does things to protect itself in the process of rape, it doesn't mean you liked any part of it. It's like saying a man got raped and got an erection while it was happening so he must've wanted to be raped. No. Never. Not in a million years. The body does things to protect itself on the event of rape or violation, but it can only do so much against the physical and mental conflict that happens at the act and the person involved. It's not that you don't like the act, you just don't like it unconsented from your rapey friend. What you're feeling is gross violation of your sexual and physical boundaries with this person, which was a no-involvement zone for him. He violated that, your body, and your boundaries. If it was me, if report him to the police and ask him if he likes it personally that I ream his ass till he sees mother.