Naps on our bed

Hi!! Currently cosleeping with my 5 month old baby boy in our bed which is raised. He is beginning to roll and I just wanted to ask what other parents do for nap time - do you use bed rails? Put pillows on edges of the bed? I usually nurse him to sleep for naps and then sneak out and watch the monitor. But just wondering if there’s a safer way to do it since our bed is not on the floor.