2 definitions by not ur dad but doin ur mom

crusty mayonnaise

A dried semen stain, usually on clothing or furniture.

Guy 1- Hey man, take a look at this stain on my pillow
Guy 2- It looks like some crusty mayonnaise

When someone farts directly into a fan or gust of wind

Dude, do you smell something?
Yeah, like somebody farted
I think it was the guy next to the fan, he just made some nasty tainted wind
What an asshole