I bought a bunny for my DD that was small enough for her to grip in one hand, with silky ears to stroke (taggie style). It was also small enough to not block her breathing at all. I kept it with me in my bra and slept with it for a couple of days. I introduced it during breast feeds and she pretty much took to it straight away. Then I went back to the shop straight away and bought a spare, and we rotated them through.