You have a couple options
1. When they bite you make pssst sound like their parents would and that should deter them. Kinda like saying "Cut that out!"
2. You can blow on the back of their neck when they bite (they hate that)
3. You can just take the bite and show them that it isn't going to make you go away
You can also limit the amount of skin they come into contact with. For the first few weeks I pulled sweatshirt sleeves over my hands to pick them up, or just one of their fleece blankies.
But remember that you will get bitten more. You are a giant to them and they are just trying to protect themselves.
