I've been bitten thousands of times. As mentioned above, defensive bites are no big deal: strike and release. Only made worse if you have time to react and jerk back, also outlined above. Feeding bites are much worse. If they realize their mistake, they release and move on. If they don't, you could have a problem. I have an adult CA King with a feeding response that just won't quit. He will sink all his teeth into my hand as far as they will go and constrict like he's trying to kill me. I'll use my other hand to try and dislodge him, and he'll wrap around that one, too, giving me "snake cuffs". If I manage to keep one hand free, I'll use a thin plastic card to slip between his jaws and my skin. This does less damage (to both of us) than trying to pull out from his teeth. Otherwise, a quick dunk in the faucet usually changes his mind about a meal, but I've spent 20 minutes with him attached to me. At other times, the same snake is calm enough to pass around to school kids with no problem. You can usually tell his mood by his actions, but they're all different.