When in the act of having sex(usually doggy style) and the male punches the girl in the back of the head.
Person 1: My head really hurts.
Person 2: What happened?
Person 1: I got gorilla fisted!
An incredibly harsh, violent, non-rhythmic hand-job.Motion should give the impression of primates in the jungle or at the zoo. Also known as a "2001" in reference to the opening scene in the movie.
" Oh man, I got so wasted last night I let this Fugly give me a Gorilla fist behind the bar! I can barely walk today...."