fart detective 

Someone Farts and no one admits to it so they get the fart detective on the case to find out who did it.

True story, last friday I was on the bus to work and someone let rip. Damn it smelled! People started to wretch. A lilttle old lady became a fart detective and searched out the culprit who turned out to John Connor after a curry.

fart detective by AGnumbnuts November 10, 2011

fart-detecting compound 

A.k.a. finely-pulverized talc. A substance utilized when you want to find out who's been cutting the cheese, but nobody's willing to 'fess up; the simple procedure involves having everyone strip down and stretch out on their stomachs, whereupon you sprinkle a moderate dusting of baby-powder on the lower half of their ass-cheeks, then watch for a "puffball eruption" --- busted!

Using fart-detecting compound can indeed be an excellent way of reliably determining "who did it", but you will want to be wary about slapping said odiferous-offender's butt afterwards, especially if you're an attractive female --- as you are all too aware, many dudes actually **enjoy** getting spanked by a cute gal (we find it fun and hilariously amusing, plus it makes us horny), and so your hot-headed attempt at getting back at said "whistleblower" may actually "backfire" --- literally! (Pun not intended, but certainly spot-on appropriate in this instance!) Said gassy dude --- and by extension, one or more of his other buddies in the room --- may then begin actively "tuning up the brass band" (and possibly even chow down on baked beans or other gas-producing delicacies to ensure an ample/continuous "supply" ) so as to "earn" smartly-administered swats from you, eventually leaving you with stinging palms and a major headache from da resulting stench.

fart-detecting compound by QuacksO December 4, 2018

Deceptive Fart 

A deceptive fart would be when you are about to fart, and just before the fart leaves your asscheeks, you realize it is in fact Shit. Therefore resulting in you having to clench said bumhole and try to suck the poo up. Can result in failure, where you shit yourself, or excruciating pain.

Robert: "Man I thought I had to fart but I shit myself."
Wesley: "That's the worst deceptive fart ever!"

Deceptive Fart by 420GanjA420 April 2, 2012