My boa would do that if I didn't give her dead prey because she simply doesn't constrict anything.. I'd hope she would if I put a live rat in there but when I switched her to prekilled, the rat could still be twitching it's back leg (nerve impulse) and she would be swallowing it.. This is a 5ft boa so it's strange to say the least. Now I wait until any twitching has completely ceased before putting them in there.

If you're concerned that your snake won't break the "lazy" habit, just switch to thawed or prekilled now and save yourself the worry.