I don't like the biting and clawing from the feeder, either. What I do is watch, and if it looks like the mouse/rat is in a position to bite the snake, I put the tongs in the rodent's mouth (like someone mentioned with a pencil) or use the tongs to keep the rodent's feet away from the snake. That way, the rodent bites and/or scratches the tongs and not the snake.

And just FYI, the "lead" of a pencil wouldn't hurt a person, let alone a mouse. It's graphite (a form of carbon), not lead.