marker butt 

What you call your ass after a bowel movement in which–after multiple wipes–you're still not clean.

The opposite of a "no wiper".

I was in the bathroom this morning 15 minutes longer than usual because I was out of wet wipes and had marker butt.

marker butt by Jon Ace April 12, 2015

Butt Marker 

A condition of the butthole that can occur during defecation. An instance when your rectum continues to supply feces no matter how much you wipe.

The imagery is that wiping yourself is as useless as rubbing toilet paper across the top of a marker. No matter how many times you wipe it it just keeps making its' mark.

1. Man! I thought I'd never get out of that stall, I was pulling a total butt marker!

2. I pulled a butt marker this morning, I ran out of toilet paper and just used a wash cloth.

Butt Marker by iapologizemom May 16, 2014