We had our son sleeping with us fulltime from birth. We just used our doona still. He was so little that placed up the top of the bed between our pillows it wasn't on him anyway. He never wriggled down but I figured when he started wriggling down he could wriggle up too so I didn't personally stress over it. He stopped sleeping with us full time a few months ago now and now he will hardly sleep with us at all. We miss him in the bed but whenever I try he just crawls around and hits us no matter how tired he is. Enjoy every precious moment- cosleeping is wonderful and feels so right.