This was a new tip I learned this go round. Early on, Oliver had a tough time with the transfer. The minute he hit the mattress, he woke up. It was oodles of fun. I proposed this to Twitter and Courtney came to the rescue with this tip. We started warming the co-sleeper at night before we got in and BINGO! He didn’t budge after putting down. Since then, he doesn’t seem to have a hard time with it but I do have a scrap of fleece under him that is warmer. That also helps with the nightly spit up fest. I don’t have to wash sheets as much!