First off, before getting into this, I ought to remind that everyone’s body is different, and it’s really, really hard for me to explain through text. And even if I did it on video, it’s on you the audience that may have it done differently. I’ll do this the best I can to explain.
- There is a muscle you can pull to cup your armpit. Raise your arm just enough, and try pulling this muscle. You could feel it going inside your armpit, drawing from the upper side of your ribcage, and that the front and back sides of your armpits stiffen and show through. If you do it just right, you cupped your armpit. The tighter the better.
- Cup your free hand and put it just over your cupped armpit. Rest the underside of your hand knuckles (just above the palm, where the fingers begin to separate) on the stiff back side of your armpit cup. Now you have a space full of air between your armpit and your hand.
- Squeeze your raised arm downward. The air should come out of between the skin of the back side of your armpit and the underside of your knuckles, even out of between your fingers, and as a result, you should get the desired fart sound. If it sounds silent, try using a different form, tightening or loosening, etc.
If you did it right, congratulations!
If not, keep it up. Anybody should be able to do it. It’s just cupped air forced out.
If you’re still having trouble with it, you can always ask someone you know that might be able to help you better.