Two guys recently wrote a book on farting . . . yes, really . . . and it has a list of 150 different terms that people can use for passing gas.  Including:  Baking brownies, booty belch, get out and walk Donald, trouser cough, and testing in the Levi wind tunnel.

Some of them are ones we've heard of . . . like "cut the cheese", "air biscuit", and "step on a duck."  But courtesy of HuffingtonPost.com, here are 22 of the slightly more obscure ones on their list:

1.  Back draft.

2.  Baking brownies.

3.  Booty belch.

4.  Get out and walk Donald.

5.  Trouser cough.

6.  Air tulip

7.  Cornhole Clap

8.  Exhume the Dinner Corpse

9.  Testing in the Levi wind tunnel.

10.  Benchwarmer.

11.  Answering the call of the wild burrito.

12.  Barking spider.

13.  Colon bowlin'.

14.  Insane in the methane.

15.  Let Polly out of jail.

16.  Tushy tickler.

17.  Sphincter whistle.

18.  Mouse on a motorcycle.

19.  Orchestra practice.

20.  Bumsen burner.

21.  Thunder from Down Under

22.  Horton hears a poo.