sniper
Hiding in a closet while two people are having sex and proceeding to beat off in the closet. Right before you're about to blow, it is the act of running out of the closet and busting a nut on them and then running away.
Example:
"You should of seen the look on their faces when I pulled the sniper on my roommate and his girlfriend"
"You should of seen the look on their faces when I pulled the sniper on my roommate and his girlfriend"