To cup ones hand over the anus in the shower, forming a tight seal. Once filled, fart into the water, making a bubbling cauldron sound.
Sorry about the smell in the bathroom, I made a particularly bubbly Witch's Cauldron.
by jeezihavenfi October 29, 2008
To pee in someone's ass while they're farting so that the pee bubbles like a cauldron.
Dude, Josh totally gave Tiffany a witch's cauldron at the superbowl party.
by Mekkanism January 31, 2008