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2.
When one shits in their pants and then shakes the poop out of the bottom of their pant leg.
I was on stage and I had to shake one out and it wound up hitting someone in the front row.
by Rob Stern September 25, 2007
 
1.
When you have to jiggle your penis to get out that last drop of pee out.
Bryan: What took you so long to take a piss?
Chris: I had to shake one out.
Bryan: Oh, I hate that.
by PenPecker August 07, 2011