This can only be done in prison. When you have to take a shit real bad and there is only one toilet to shit in and it is in use. You sit on the other shitters lap, while he spreads his legs slightly to allow your shit to drop between his legs into the bowl.

Also known as David Hasselhoff's White Christmas
"Man I gotta take a shit but someone is on the only shitter!"

"Guess you'll have to do a tandem mudslide"
by gangster_hops October 14, 2009
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