Whenever Bucky wants to take a nap he wrestles Steve onto a bed or couch so he can lay down between Steve's legs and lay his head on his chest. Bucky does this because Steve's arms are the only place he feels safe. At the same time he always has a constant need to watch out for Steve. In this position Bucky can protect Steve and Steve can protect him. If Steve isn't home Bucky will simply not nap. Even after all this time he can't bring himself to sleep while vulnerable.