Excited Ferret Chews Its Butt

Q: Why does my ferret chew his butt when he gets excited?
 
A: I don't know for sure, but I can only guess your ferret is so excited and worked up that it doesn’t know what to do with itself. Because of this, it runs around and its tail is moving fast, so it attempts to catch it and ends up catching its butt.

This behavior also could be related to the ferret’s scent glands. When they get excited, ferrets that are not de-scented can "poof," and they are trying to smell it.