Ah, I misinterpreted your statement to apply to in general.
When it comes to the case in question; I suspect wether consent was given or not will be one of the disputed points in the case. I still think he might've agreed (but that it might have gotten out of hand).
Clearly this guy is overreacting. All he had to do was put on a full suit of body armor after he banged her. I'd still hit it.
Even drunk, if he consented to some light knife play, I doubt he consented to being fucking branded. There is a difference between saying "Ok, a few light cuts, I guess I'll try anything once." and "Oh holy hell did Edward Scissor hands feel me the fuck up?"
One of these things is not like the other.