I needed to do this for a month or 2, as one of my snakes wouldn't eat frozen when I got him.
If you stun them right, the snake will kill the snake in less then 10 seconds, and a heavy stun is usually lights out for a few minutes, but they still breathe, still twitch, and still have a heartbeat, so the snake will accept them.
As long as you feed live, there will always be a potential for bites, that's why I try to feed f/t or harmless baby rats, but the snakes always seem to do their thing.
I make sure to watch then until I see the tail disappear, as sometimes even when a snake constricts them they can wake up a minute or so later when the snake lets go.