1. When you can smell your fart in another person's fart.
2. When two people fart at the a time .
Ashwin : I farted
Josh : You nasty F*ck ! Your insides must be deteriorating and rotting to produce a foul smell like this.What the hell did you eat !? *farts*
Ashwin : =.='''
Josh : I farted too..Oooh the aroma, the texture, the profound nature of it all, this is the art of a genius encapsulated in gas
Ashwin : Basically, you can smell your fart in my fart.
Josh : It's a fartception !