Human Tromboner
It consists of blowing into the receivers anus while firmly grasping the gonads and you can probably guess the boner part, in order to emit a symphony of weird noises.
Man 1: Becky gave me a human tromboner last night
Man 2: that sounds like it was fun
Man 1: yeah she played my ass like a jazz tuba
Man 2: that sounds like it was fun
Man 1: yeah she played my ass like a jazz tuba