Fiery liquid poo that tends to spray itself all over the inside of your toilet bowl. Spicy Spam is one of the worst known offenders for "rim of fire", and can cause multiple trips to the bathroom. So many trips that you to wipe your ass raw, keep having to poo, wipe, poo, wipe, poo, repeat. The poo is so acidic it burns your poor heiny alive. It's best to listen to Johnny Cash's "Ring of Fire" while enduring the pain.
I fried up some Spicy Spam, and was so hungry I ate the whole can. On top of that I had some habanero cheese and an entire bag of Flamin' Hot Cheetos (mmmm). Rim of Fire! Yow!
When your cover your cock in gas or oil and destroy someones butthole. Then throw a match burning their butthole out.
Yo dude last night I gave the best rim of fire, i burned her asshole out