Gravy Leg

When a person accidentally, purposefully, or excitedly defecates his/herself and the excrement runs down the leg. As defined by Opie and Anthony.

Mark crapped his pants today and had a bad case of Gravy Leg.
This movie is so funny its going to give me gravy leg!
I really didn't feel like going to class today so I walked in with Gravy Leg and the teacher excused me.
I went to squeeze out a fart and ended up with Gravy Leg!