DS aged 15 weeks is obsessed with his new rolling ability. Keep finding him face down in his cot though fast asleep. He doesn't even turn his face to the side. I roll him back onto his back and next time I check he's on his tummy again. I know once they can do this apparently they can get themselves out of trouble but sometimes when he rolls in the day he gets stuck. Any advice please; can't stay awake all night to turn him obviously but can't sleep with worrying about it either.