An unusual athletic maneuver used for excretion. The "barn dropper" shimmies up the stall wall in a public restroom with a high ceiling. With one foot on top of each side wall and the pants dropped, the barn dropper lets go with the dump. A successful barn drop results in the target (the toilet) sucessfully hit. The barn drop is a common tactic in men's dormitories and frat houses across the USA and often done in the presence of a large, loud drunken crown of well wishers and spectators.
"Damn, the other night we got back to the frat. I heard all this commotion, and there was a huge crowd at the party chanting while Jack was doing a barn drop. He missed the target. The janitor resigned the next day."