Mouthing, nipping, biting is totally unacceptable behaviour! It took me patience and immediate correction to alleviate this problem with Cody. I tolerate alot but never anything oral. Even when he's playing, I put an end to it immediately. We covered this on another post. I usually pull my hand away and yell "ow!" "no bites" and it stops. His main passion are my alpacka lined thick leather gloves I use at night when I walk him. Cody thinks they are up for grabs and destruction. Since at that point I have his leash on, a quick jerk stops him to. If he does this to me, he will not differentiate other people. Be alpha girl!! Stop it NOW cause it will get worse!!!