DS2 (almost 5 months old) has been intentionally rolling from his back to his tummy for a month now. For the past few weeks it's nigh impossible to have him on his back for any length of time, he just rolls straight over. He soon gets really frustrated because he can't move then - can't crawl yet, and doesn't seem able or willing to rollback over to his back (we practice/assist rolling him back over, but he is immediately back onto his tummy - even though he seems very unhappy there).
This alone is becoming very tiring as he whines all day long and won't sit in highchair for more than 5 mins either.
My main issue is he has started rolling at night. He is in a grobag but it doesn't help stop him. And although he has fallen asleep on his tummy once or twice, most of the time he just cries once he is on his tummy and we have to flip him back, and so the game continues several times during the night, so none of us are getting any sleep.
Any suggestions or experiences? How long does this phase last and what stops it? He doesn't seem interested in learning to roll back (we are trying to encourage during play etc). I don't think my DS1 went through this as he was much older when he started rolling and was moving about in other ways by then.