... material What is whoopee cushion, how to make it so funny?a whoopee cushion, also known as a poo-poo cushion and Razzberry Cushion ... edges. There is a small opening with a flap at one end for air to enter and leave the cushion.To use it, one ... air out of the opening, which causes the flap to vibrate and create a loud, flatulence-like sound. Loosely imitated, this sounds ...