ass smudge 

When an offensively fat individual sits down on the toilet, misses the centre and leaves a gross shit stain on the back edge of the toilet seat.

Timmy: I swear if Simon leaves one more ass smudge on the toilet seat I'm going to flip.
Craig: Man he can't help it, he huge.

ass smudge by mattpacer May 15, 2016

ass sludge 

what comes out of your ass after taking colon blown.

Thought I'd have to call a plummer cause the toilet was packed full of ass sludge.

ass sludge by Pete the Plummer February 8, 2004