To masturbate by inserting one's fist into one's own orifice or orifices. Artificial or disembodied fists may also be used. The word is a hybrid of "Fisting", "Masturbating" and "Sophisticated", and as such could be considered a sophisticated form of self-fisting.
"I wouldn't go in there Gavin, Tylah is Fisturbating."
Bryce: "Dan, if you don't sort that shit out my fist will be up your ass"
Dan: "I can fisturbate MYSELF!"
The act of facebook raping yourself, to make it seem like you have friends who play tricks on you, but you don't really.
P - Hey look at Joe Bloggs' status, it says "Joe is really gay", he's definitely just been fraped!
M - Nah, Joe Bloggs doesn't have any friends, he's definitely just facesturbating.