We knew he was getting close because it seemed like he'd be almost there and he just wouldn't quite make it over! Then, mom called me at work to tell me had done it!! When I went to pick him up that day, we tried but couldn't get him to repeat his trick. I thought for sure mom was lying. :) About a week later, she called again and said that he had rolled again and this time, she had my dad witness it. So again, I go to pick him up and we try again and...nothing!!
A few days after that, Drew was having some tummy time and all of sudden, he rolled himself over and continued to roll himself over like he had been doing it his whole life for the rest of the day. Now he will only do it when he absolutely feels like it. We think he forgets from one day to the next!
For stats sake, Drew was 3 1/2 months old when he first rolled tummy to back.