Lets think of a situation, stormdragon is a young girl (not too hard to imagine) and mattj is her boyfriend.

Storm - I dont want to do _______ with you
mattj - Please?
storm - no, dont come near me, I already told you i dont want to.
*matt grabs/approaches storm anyway
*storm punches matt in the head.

Those are the two points id say you could strike another person in a rapeish type of case. Anytime before that and it would be hard to prove that it was in sd, but if its neccesary, then do it. I think the court would be able to tell that the 15 year old girl didnt hammer her 16 year old boyfriend for no reason.
"They say the only way to kill a lion is with a rear naked choke, but I'd just kick it in the head"