n. stance taken to effectively relieve yourself, usually during an intoxicated state, in extremely crowded areas, i.e. concerts, tailgates, wet t-shirt contests, and/or food and beer festivals (when walking to the restroom is just not an option)
You are at a crowded concert and the headlining act has just taken the stage. Suddenly, the urge to pee hits you! Everyone knows the lines are long in the bathroom and it will take forever. The only other option is the one knee pee. You assume the one knee stance, pull up your pants/shorts leg past the knee that is touching the ground, pull out tool and let it fly.
Warning: the one knee pee works best under cover of darkness and only in extremely crowded areas. The author of this message is not responsible for anyone who attempts to pee uphill or into the wind.