a fart's chance in a windtunnel 

(n.) A situation where an idea or thing has very little probability of existing or continuing to exist. In the same vein as "a snowball's chance in Hell," except less dependent on Christian ideologies.

Based on the idea that a mass of flatus has very little chance of being smelt if it is whisked away by the high-velocity air currents native to the windtunnels used in aeronautics testing.

Your new newsblog doesn't have a fart's chance in a windtunnel unless you plagiarize the shit out of other more prominent newsblogs.

a fart's chance in a windtunnel by jableshables August 20, 2010

McDonald's fart 

When you can't distinguish a scent from a fart or stale McDonald's, the mystery smell is referred to as a McDonald's fart.

The elevator in the Hallowell Building smells like a McDonald's fart.

McDonald's fart by A-roo February 5, 2007

sparrow's fart 

The earliest time of the morning. About the time when all the sparrows get up and let out a little fart signifying their awakening.

I gotta get up this morning at sparrow's fart. What a raid.

sparrow's fart by Traffic-Cone-Liberation-Force June 29, 2006

Shrodinger's fart 

The moments when, feeling the fabric leave your arse cheeks, but it could be either a large fart bubble or a sneaky poo. Unsure if it's fart or shart, it being considered to be simultaneously both fart and shart until your pants are dropped & the remnants observed.

"Oh man, I had way to much Guinness to drink last night. I woke up this morning and had to run to the loo after a Shrodinger's fart"

Shrodinger's fart by ShrodingerFart May 22, 2016

Schrodinger's fart 

an ambiguously ominous pressure in one's bowel that is simultaneously flatulence, diarrhea, and a bowel movement until it is released, at which point quantum superposition ends and one must simply hope that they guessed correctly.

It's a good thing I went to the bathroom for that Schrodinger's fart, or else it would have been messy.

Schrodinger's fart by Squeaky Farts January 7, 2021

witch's fart 

the smell of a low quality lager

When I opened up that bottle of Hite, it smelled like a witch's fart.

witch's fart by aishibai February 9, 2014

Devil's Fart 

Last fart before a poop. Usually the worst smelling after a long line of farts. The Devil's fart lets you know that if you try to fart again, a poop might come out.

Sean has to rush to the bathroom because he just had his devil's fart.

Devil's Fart by al and sean December 22, 2008