Following someone into a bathroom, preferably into the actual stall, while at the same time taking your penis out. The idea is to catch the person unawares so that when he/she turns to sit down, your junk is in their face. An erection and/or wanking are optional moves.
That dude totally pulled a sneaky petrash last night at the ceremony and almost made her shit her pants.
by MVHSnonperverts June 5, 2009