When pooping in a public restroom stall, this is any individual that is also pooping in an adjacent stall, either on the left or right or both. Having one or more Pooping Partners is generally undesired as you are often subjected to your Pooping Partner's loud grunts, snorts, and flatulence as well as having to deal with the smells of your own defecation mingling with theirs.

when you're hungover as shit after a spending a night drunk as a skunk