The crusty residue found on the underside of the toilet seat/ bowl. Usually caused from the anal explosion that follows a night of consuming large amounts of cheap beer.
Dan drank a case of bush ice last night and this morning there was butt splatter all over the toilet.
The wet, splattered butt you are left with after a high velocity oatmeal type dump. This is often the result of eating a lot after a long drinking binge. Most often splatterbutt sessions are followed by a shower and a serious scrubbing except in the case of college freshman.
After the kegger the other night we went and killed a couple of jalpeno meat lover pizzas. I spent the whole morning with splatterbutt and had to shower four times.