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
by Magnumus Dongus August 11, 2018
Get the Human Tromboner mug.