Term that refers to that little dribble of piss that totally screws up the front of your pants. It can happen as a circumstance of your boxers getting in the way or from dribble when you put away your junk. It's what happens every time your Grandpa goes to take a leak.
"Fuck! I just Grandpa'd on the front of my new dockers..."
by Aaron Stein December 17, 2003