Its when prisoners tie a rope to the soap so they cant be fucked up the ass if they drop the soap.

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

An item prisoners use when showering so that the soap cannot be dropped and then the person becoming subject to harsh anal sex

1: literlly soap on a rope
2: a highy comical idea, that can cause laugher for hours

Slang for the Pope's penis, because they're "both pointless unless in prison," according to Bo Burnham.