Naturally, it only dawned on me AFTER I finished this strip that maybe not everyone's familiar with the gesture made in the final panel.

When we were kids (I grew up in Maryland, if that makes any difference), if you heard or smelled a fart, you'd immediately slap your thumb onto your forehead to indicate to potential fellow fart-smellers that you were NOT responsible for that foul smell.

And what if you were responsible? Well, you'd give it away because you'd be the only one giggling about it.