When someone takes a crap on a campfire so that the turd rests on a piece of wood and slowly roasts, stinking up the entire campsite. A slowly burning/melting turd.
"I burntmy ass hairs off making that Melty Log over at the girls campsite!"
"Dude, it was so worth it though. I can hear them screaming"
The excruciatingly hot poop that comes out of your butt a day or two after eating spicy Mexican food. It feels like your butt is being burned at the stake like a witch. The hot log leaving your body.
I added extra jalapeños to my burrito and my butt burns so bad you would think it was a Mexican Salem burning log coming out of my butt.