My foster kitty, Mickey, can get bitey, and that's not good when I'm trying to help find him a forever home. In fact, our first prospect lost interest when she saw him play bite. Yikes!
After noticing this was a habit, I turned to Tracey Toole, Co-Founder and Director of A Tail at a Time, for advice. She gave some sound advice that worked for me and my little Mickster:
If kitty is playing with your hand, get a plush toy he can use as substitute for your hand. Try to do this before he nibbles.
If kitty starts to bite and grab the hand/arm, tell him "NO" firmly and get the hand away. Kitty will likely pause and wonder what he/she did. Then you give kitty the toy and encourage them to grab it and play with it.
Make sure the toy is not so small that the cat can't rather hug it and really go at it. So a little mouse toy won't work. And it must be plush, so a plastic bell ball won't really do the job either.
Some tried and true ones are the Kitty Hoots from Fat Cat found here: http://www.fatcats.com/html_site/cats.shtml My childhood cats' fave was the Newt Hoot!
So in summary, stop the action with a firm but not too loud or angry "No", and give kitty the toy to play with, and play with it a little to show him it's the play alternative.
Lastly, don't use your hand as a cat toy. Cats that develop a connection between hands and playtime may nip and bite anyone that goes in to pet them, such as guests or, if he/she is a foster, prospective adopters.
Mickey loves the feather stick http://youtu.be/pdj0oyt_w_c
Mickey is still up for adoption, so spread the word!
http://www.petfinder.com/petdetail/18698965
by Courtney Kistler, foster and Rational Animal Rep. www.rational-animal.org