The act of thrusting your hips forward and backward in order to make your codsack flap backward and smack against your ass cheeks, causing a clapping noise.
Person 1: "Dude I totally Codsack Flapped last night!"
Person 2: "Really?! Did it hurt?"
Person 1: "Hell yeah bro!"
Person 2: "Really?! Did it hurt?"
Person 1: "Hell yeah bro!"
by iAmHunterific November 02, 2018