This joke describes the biggest fear of prisoners in the US. If you drop the soap in the prison shower, you're in the perfect position to be raped! The term is usually used in humor.
"Don't drop the soap". A good example is in Dave Chapelles movie Half Baked where a character who gets locked up drops the soap. Dont drop the soap!! He gets preyed on my Nasty Nate
von Jamaal Smith 29. Juli 2006