Whoopee cushion

A whoopee cushion, also known as a poo-poo cushion and Razzberry Cushion, is a practical joke device, used in a form of flatulence humor, which produces a noise resembling a raspberry or human flatulence. It is made from two sheets of rubber that are glued together at the edges. There is a small opening with a flap at one end for air to enter and leave the cushion.

To use it, one must first inflate it with air, then place it on a chair or squeeze it. Some whoopee cushions can be self-inflating. If placed on a chair, an unsuspecting victim will sit on the whoopee cushion, forcing the air out of the opening, which causes the flap to vibrate and create a loud, flatulence-like sound.