A butt slug is a slow moving, small piece of poop that takes forever to force out. It leaves your ass as fast as a slug would...very slowly. It can sometimes look slimy in the water and leave a trail on the toilet when flushed. Unfortunately, when you pour salt on a butt slug, it does not melt.
An example of a butt slug would be a small, slow moving piece of slimy poop that takes forever to force out and leaves a trail on the toilet when flushed.