fartual
The process that an individual goes through in the moments just before passing gas. It can be as simple as a blink of an eye, to an announcement such as, "Hey everyone, check out the sound I plan to make with my asshole!"
Bill: Ugh, who farted?
Sabrina: Tim did. I know his fartual; he scratches his shoulder just before he farts.
Sabrina: Tim did. I know his fartual; he scratches his shoulder just before he farts.