I have used a trigger method to train ferrets not to bite.  You place your
forefinger into their mouth sliding it to the back teeth and put your thumb
on the back of the neck while repeating "NO" in a harsh tone.  The ferret's
back teeth don't hurt you (if you're a little skittish about sticking your
finger in a ferret's mouth, wear a glove).  Since the ferret doesn't like
the feel of having the finger in its mouth, it will eventually stop trying
to bite down on it.  It works beautifully and nobody is traumatized by
this.
 
As for the feet biting, my gang will nip at my feet if I paint my nails.
I guess it's just a ferret thing.
 
Hope this helps...Joelle and the 3 fuzzies
[Posted in FML issue 3060]