The act of one man flicking another man's penis with any object besides his hand (to avoid any homosexual accusations), the flick must be brisk and gentle so said man does not get injured. While in the process Man 1 must shout "Shifting Gears!"
Man 0: Bro, you gotta go shift gears...
Man 1: I got it... *proceeds to 'shift gears' on Man 2*...SHIFTING GEARS!
Man 2: You're dumb.