I guess you're referring to the situation that someone starts sleeping on back but wakes up in different position? I haven't gone that far - last night I was ju

I guess you're referring to the situation that someone starts sleeping on back but wakes up in different position? I haven't gone that far - last night I was just lying down couple of hours, very tired and sleepy but unable to fall asleep while lying on my back. Eventually I gave up, decided to ask HN, turned on my side and slept like a baby till morning. I was a little bit late at work though.