How do you make armpit fart sounds?

First, make your hand in a cup. If you're left-handed, use your left hand, and if you're right handed, use your right hand. Now, open your other armpit, then put your cup-side up hand, and push down. May take a little time to master. I AM A MASTER AT THIS! My record: 18 seconds long. Another my record: with tools, measured at 102 decibels! LOVE watchin' burpin and arm fartin videos.