Pull up blankets are the best idea. They are like a sleeping bag that goes over your mattress. One side is fleece for winter and the other side is cotton for summer. I got a single bed one and a cot one made and my girls stay under and dont get cold in winter. Both ends are open incase your little one slides under. The lady is really friendly and a great communicator. I will be ordering another single bed one soon when my bub goes into a big bed.