DO - remove any hides, ground cover, sticks, bowls, basically anything that the feeder can hide behind, chew, or will impede a clean strike.
DO - gently place the feeder in the tub, 99% of the time they don't even realize the snake is a threat, it just looks like a piece of cage furniture until it suddenly whallops them.
DO NOT - attempt to stun, confuse, or disorient the feeder. That will escalate what would otherwise have been a calm, curious exploration of a new tub to an atmosphere of frenzied panic.
DO NOT - leave a feeder unsupervised in the tub