What Is That Sound?

On this track, the Angry Housewives get a groove going only to be interrupted by . . . well, I'm not sure what that sound is.  Maybe an engine backfiring?  Someone farting?  Someone flapping his lips really quickly?  A deck of cards being shuffled loudly?  With the Housewives, one can never tell, and I don't remember.  Other than that, it's the usual noisy guitar and beating on pots and pans.  And just like you probably, I have no idea what the hell we're screaming either.