third-degree fart

Unlike a mildly-to-moderately-heated first- or second-degree fart that may merely cause minor reddening and/or blistering, this term refers to a super-hot expellation of concentrated putrid methane that not only broils Uranus and singes your butthole-hairs on the way out, but it also scorches the thigh/knee of any unfortunate fellow human being who happens to be unsuspectingly holding you on his lap at the time! It is wise, therefore, to be constantly "aware" of your colon's current "status" or "progression" of fart-activity whenever you're canoodling with someone, so that if you "feel one on the way", you can hastily hop off (here's one case where your lover most definitely **won't** think you rude or anti-social when you abruptly/wordlessly bounce up off his lap) and direct your posteriors away from your snuggle-buddy, anyone else within a fifty-foot radius, and of course, any source of fire (yes, farts are VERY MUCH flammable!), such as the outdoor grille that's currently frying up another big batch of the same beans 'n' hot wings that made you have the awful flatulence in the first place.