The sweat-soaked flecks of toilet paper that accumulate in ones' butt crack during the day. This term applies mostly to women as men's butt cracks usually contain large amounts of poop and other filthiness.
Aw shit Danny you used the last two slices of good bread left for your toast last night. Now I got these asses left to Make a fricken peanut butter jeally Butt sandwich, boy is work going to suck today!
Also known as the “Nut-on-a-butt” sandwich, when a guy fucks a girl from behind, nuts on her crack and smooshes the cheeks together, creating the nut butt sandwich.