And if you're pregnant, try to sleep on your left side rather than your back.

I put a light dressing over it and said, "Don't sleep on your back."

He'd been sleeping on his back and he woke up without moving.

This will certainly stop you from sleeping on your back!

It looked as though a polar bear were sleeping on his back.

I did not like to sleep on my back.

"It only seems to happen when you sleep on your back."

This will help keep you from sleeping on your back.

It is attributed to result from a person sleeping on his back.

Sleeping on her back was uncomfortable, especially with a tail.