brown trombone Share definition Flag This is when you are standing up and a girl is eating your asshole out and jacking you off at the same time. Me and Suzy skipped band practice and went behind a bush where she gave me a brown trombone. brown trombone by GG January 25, 2004 0 0 Get merch Get the brown trombone mug. Buy Now — $32.95 See more merch