It happens after you eat to much spicy food, and it causes you to fart in a burning matter as if someone shoved a blow torch in your ass.
Husband: Thank you hun, That was the best spicy enchiladas ever.
Wife: You're welcome *Smiles*
Husband: *smiles back and Farts* CHRIST!!! WHAT THE FUCK DID YOU DO TO ME?!!!
Wife: Are you O.K.?
Husband: that was the worse pyro-fart ever, My ass is still on fire.