Well, as a cat, he will be in that "mood" fairly often, so you'd better look for or make a substitute for your arm. Otherwise, when he does that to your arm, don't resist, just go limp. If you struggle and try to get away, you will be playing into his hunting instinct, and he will clamp on even tighter and start biting.

To him and his cat imagination, your arm is a wild creature that he wants for dinner.