when you use someone's butt cheeks as a tortilla and fill in their ass crack with burrito fillings--pinto beans, shredded chicken, salsa, sour cream, and perhaps a special sauce from their anus-- and then eat it.
Timothy was upset that Tina's butt burrito didn't have sour cream in it, but he ate it out of her ass crack any way.
A huge solid turd, especially very thick turds that cause pain when excreted. The blood accompanying a butt burrito is sometimes known as "special sauce".
She sure is taking a long time in there and making some terrible sounds... Must be laying a butt burrito.
Oh man! I just made the biggest butt burrito! I clogged the toilet!