Perhaps this is an example of regional variation. As an American, I would first assume the person had peed themself, but of course pooping also makes sense here... either way, a change of clothes is definitely in order!

Hi Priscilla, Yes, as Debora mentioned below it means to "poop" (in your clothes by mistake). I feel very sorry for the unlucky actor! Jamie (www.italki.com/jamie.teacher)

I think it means to "poop"...