What word should I use to describe a kid who has pooped in their underwear?

I have seen some kids who can't go to the restroom in time and their poops stain on their underwear. I would like to know what word I can use to describe this situation?


Solution 1:

I'm probably going to regret this, but the vulgar and casual expression you are looking for is skid marks, the bane of laundry day.

Solution 2:

Encopresis is the medical term to describe it.