I was gonna buy the mesh crib liner, but that doesn't really help if LO bumps her head/body into the rail and cries... So I'm back to thinking about buying a regular padded crib bumper. She is almost 5 mo and doesn't really move when she sleeps (for now since we put her down asleep). She also had slept on her tummy w/o issues between like 2-4 mos.