A loincloth. A term used first in George of the Jungle, but most notably in George of the Jungle 2.
"He keeps the deed in his what?"
"His, um, butt flap..."
1. Gays, queers, and homosexuals alike.
2. Having to do with or a general adjective for feminine things.
Honey, I'm not wearing this shirt, it looks like it's from the Cashmere Mafia!