...why would you feed a snake while its being handled or rather, wrapped around your arm? Are you sure you are feeding the snake enough?
If you want to pick up a snake who looks to be in a bad mood, just approach from the side so they can see your hand but can't turn to bite quickly enough. Then scoop em up and hold them until they relax a bit. Don't wave your hand in front of the snake first and let it smell you. You are just giving it more of a reason to bite you (especially if it is pissed). They are not dogs or cats, they don't need to smell you before you pick them up.