Whoopee
A test of one's security is what you do when you sit on a suddenly "squeaky" seat cushion eliciting a sound that mimics that of an embarrassing sound associated with a body function. Most people will try to reproduce the sound to "prove" that is was the couch/chair rather than him/her. Odd behavior, but most of us seem to do it.
Perhaps the more interesting case, though, is when the sound really is from the person. This isn't particularly common, as most people have sufficient self control (as opposed to the "eight year olds" who actually make an effort to be coarse). But what does a person do, and what does the "listener" do, on those rare unfortunate occasions? In polite and professional circles, the sound never happened. It is just ignored, presumably not to embarrass the "offender." In impolite or unprofessional company, the crowd reverts to a pack of eight year olds in persecuting the "offender," and there are few things funnier than embarrassing body functions to an eight year old (and most men are eight year olds in bigger bodies). Of course, many of these "offfenders" are intentionally so.
There is a middle ground. A simple "pardon me" is actually kind of classy for those times when one couldn't get to the lavatory and light a match. (I actually dated someone who used to do that. Kind of quaint, really). Or maybe a little joke ("Oh, the geese are flying low.") and then just move on. And move on is the key.