Poop sock

A sock used to defecate into, typically shared amongst siblings during playtime to avoid leaving to use the bathroom. A big mistake that's made is the when children grow up, they don't grow out of the poop sock phase. Either that or the middle child will take the poop sock and smack it against the wall spreading the poop all over the wall.

The youngest: Who has the poop sock? I need to go really badly.
The oldest: I think your big brother took it.
The middle: Guys, emergency! Mom found the poop sock!