With the rolling onto his back, that's a developmental thing and like all new skills they learn, they will practice when they're meant to sleep too

. So I would just leave him until he needs you and if he is calling out for you (cannot settle on his back), you might have to do some shh/pat rather than flipping him over because he will depend on you to come to the rescue all the time. Like you said, plenty of practicing during the day is good... This is something I don't have experience with because mine sleeps on her back but we will probably start to have this issue when she rolls onto her tummy

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I am also wondering whether you weaning the 4am feed was a bit too early? do you think he might be hungry? have you tried feeding and putting him back to sleep.... at this age, most still have 2 (or 3 night feeds) and I probably wouldn't be cutting down night feeds until a little later

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So is he sleeping morning and afternoon nap 1.5hrs and a catnap?