How quickly do you go in there and give it back if you do? When our ds did that with his paci, it was a game and dh was determined not to give it back to him at all to teach him (it has been a very long time since he has done this), but basically when he would throw it out I wouldn't go back in there for quite a while as I gathered that he wasn't ready to nap when I put him down. Usually if I left him in his crib, then went in there and gave it back to him after a while (and the most I could probably hold out for was about 15mins or so), he would usually be ready to sleep by then or be so appreciative to get it back he didn't do it again. That seemed to work for us and it was only ever a short phase he went through. HTH