NASA - Ass Share definition Flag When you have explosive diarrhea that is so bad that it virtually or literally lifts you off the toilet seat (like a NASA rocket). "Don't go in that stall, Leroy just had NASA - Ass in there!" NASA - Ass by JamBro November 12, 2005 0 0 Get merch Get the NASA - Ass mug. Buy Now — $32.95 See more merch