I know babies are supposed to sleep on their backs, but mine keeps turning over on his tummy. What should I do?

My son did that when he is young he always sleep on his tummy! Guess like that he feel more secure and comfort ! This way he can sleep longer and reduce on crying! Most importantly is that make sure he is not suffocated and they will change the way they sleep when they are older! Now he sleep by the side he didn't train him to sleep that way now he prefer !