some people do that ^^^ for the thrill, i fucked my wife on my best friends couch in the living room once...i don't think they were sleeping either....even if they had walked in tho they woulda laughed and walked back out, we're a very "open" people for lack of a better word.
as for the original question...i kept wondering how the bitch managed to break my dick when it doesn't h ave a bone in it....i felt it "snap" and great pain...she was trying to ride me and didnt know what the fuck she was doing (obviously).....to this day i can still bend it in half (while hard) and i can pop it, like you would crack your knuckles....