an acronym for the popular phrase; "On My Way To Fuck Your Bitch." This condensed acronym version is often used as a tag on pictures concerningspontaneous and often whimsical forms of motion and transport.
Bill: Dude this fat guy's on a slip&slide ripping down a hill
Dale: LMFAO DUDE, post and tag it OMWTFYB
Guy1: Oh, by the way. I slept with your wife.
Guy2: OWTF!?
Guy1: Yeah, we got pretty drunk, and when we woke up next to each otherin the morning we were both like "OWTF!?"