when playing pool (english) and the black is sunk (potted) whilst one player still has six of his/her balls on the table, he/she must remove their trousers and underwear and walk around the table
(alternatively just the trousers. (or top for women))
see also five balled and seven balled
"oh shit! im gonna get six balled!"
"haha get ready to drop 'em!"
"oh man i knew i should have worn underwear today!"