Crude but descriptive term for two people trying to show which is superior in some dimension, often knowledge, ability, or power. Somewhat sexist, but it seems to be a male thing. -- RaySchneider
At which point the female Marine dropped her trousers and drawers, arched back and put her hands on the ground (in the "bridge" position) thus aiming herself in the appropriate direction, and proceeded (using the pelvic muscles that men lack) to deliver a stream of urine that went twice the distance of the best effort of the men. Having demonstrated the inherent superiority of the fairer sex (and more importantly, the US Marine Corps), she then pulled up her pants and went merrily on her way.
That would suggest that she practiced somewhere before. Otherwise, she would not know of her abilities.
This term may come from an old joke in which two guys are pissing off (opposite sides of) a bridge. To impress the other, one guy says, "This water's cold". Not to be outdone, the other says, "Yeah, and it's deep, too!"
The solo version is sometimes called Willy Waving. A quick remedy is the PissTake.
See also: HolyWar