1 definition by Bruno Strongarm
Where you jerk off under someone's bed to scare them. Upon finishing, you shout "HAPPY HALLOWEEN" in your scariest voice.
"Hey, Jimmy, what did you get up to for Halloween. Costume party?"
"No, I just went on a monsterbation spree. Scared the little bastards senseless. It was both a trick and a treat."
"This friendship is over."
"No, I just went on a monsterbation spree. Scared the little bastards senseless. It was both a trick and a treat."
"This friendship is over."
by Bruno Strongarm March 17, 2014