placing your balls above the waist of trousers but beneath your tshirt, and then lifting up your tshirt to reveal your balls to random strangers whilst shouting "plong"
Hey Chris! What? PLONG! Dude put your balls away!
by Harrrrryyy06 August 22, 2010
An unsual noise created by a elephant trapped in a jam jar.
"Can you hear that plong!"
by Felix_T May 14, 2008