Ugh, we've had this happen multiple time with Katie. I do it as part of wi/wo when I need to -- I'll go in there, tell her, "time for sleep, here's your bunny" and walk out....wait until she does it again and cries for 5-10 seconds and back in and repeat. I don't react at all to the lovey being on the floor, just pick it up and act very matter-of-fact about it. Sometimes I've had to sleep on her floor and then I'll do much the same thing, though her bunny is small so I can push it between the bars of her crib.