to have a urination go really bad for whatever reason. Includes spraying urine everywhere because you tried to piss with a chubby, or having your urine shoot out at one or more 90degree angles due to being gum shut, or any other bad thing happening when you're taking a piss.

Combines 'piss' and 'disaster'.
Dude1: What the fuck happened in the bathroom?
Dude2: It was dark and the lid was down -- a classic recipe for pissaster.
Dude1: Well fuck, clean it up!
by Figleaf23 August 5, 2007
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