A burrito which has been warmed using a bathroom radiator, usually while wrapped in foil.
"Just had a great bathroom burrito."
"Was it good and hot?"
"Yeah, that radiator has been cranking all day."
a burrito that you heat up in a 1130 WATTAGE microwave and leave in the bathroom for 3 hours waiting for your daughter to eat.
mom: who ate my bathroom burrito??
me: oh. i did.