Everyone has a shitty day once in a while. Fireass is when your ass gets irritated by sweat activating the fecal matter left behind from a sub par wipe after shitting.
More common on hot summer days, fireass takes several hours to develope, and has different levels depending on the intensity of discomfort experienced.

Referring to the heavy unfashionable winter jacket and patterned mittens Sanders wore to the inauguration of Joe Biden.

When you go to Taco Bell and your smomach starts bubbling and you have massive diarrhea. After you stand up and your ass is burning, the sensation is known as "fire ass".

Eating lots of spicy food then burning your ass hole while shitting.

A condition when excreting feces (taking a dump), your anus literally feels hot as a result of eating too much spicy food.

"amazing" or "really good"

Used to describe a desired subject; often a compliment.

Usually used in a sentence before the actual subject.

Fireass is also known in the UK as Chef's Arse, the result of working in hot sweaty kitchens