I have a niggling little worry about placing baby to sleep on his back. Sorry if it's a silly question, it just pops into my head each time I think about only ever sleeping on his back. What happens if he vomits?? Does his coughing reflex kick in and he'll be ok? or what?

I know it's recommended they sleep on their backs for SIDS reasons, but I just can't help worrying about that bit of overflow or vomit if he's flat on his back.

Can someone put my mind at ease that he'll cough like anyone else would, and not just silently choke?