Tongs in hand, drop in rodent, observe with patience until the snake strikes. The rodent will seldom bite your snake; mostly they're just scared. After the strike, roll the snake over if you have to in order to see if the rodent's mouth is exposed and could do damage to the snake. If the mouth is exposed then put your tongs or a pen or something in the mouth to stop the rodent from biting. I've had to put my tongs in a rat's mouth a few times. It's just part of the hobby, and part of being a responsible snake owner. Generally you just have to hold it there for a minute or so before the rat is dead or gives up. In my experience none of this has ever put off a snakes appetite.