omaiyuwaiyu
Originally it meant : "I am going to fuck your bitch and steal your shit " ,but in the recent years it changed to an expression for sex and illegal stuff in generall.
Guy 1: Hey Thomas, what did you do this weekend?
Guy 2: Omaiyuwaiyu.
Guy 1: You are a real gangster Thomas.
Guy 2: Omaiyuwaiyu.
Guy 1: You are a real gangster Thomas.