skinny tuba

When you put the mouthpiece of a tuba into a girl's asshole during oral sex and she farts

You: I was going down on Jenna and she wanted to try out a new move, so I got my old tuba from the garage and we tried to skinny tuba.
Jerry: Woah bro, did it echo around the house like I told you it would?!
You: Hell yea it did bro, even the windows were shaking!