Top Definition
The jet of urine which bouces back from the toilet bowl and up to the nether regions of the toilet-sitter, caused by expulsion of a urine stream with excessive volume or force.
Jane: "After those two pitchers of pabst I peed so hard I undersprayed."

Jill: "You're an alcoholic. And you smell like urine."
by Nerdiva March 28, 2011

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.