My daughter has had a duvet in her cot for about 2 months now at least, maybe 3, and she not once has had it on her to sleep. She’s scared of it and when I put it on her she kicks it off crying 🤷♀️ so I leave it at the end of the cot. She doesn’t really wake up much in the night though and I haven’t found it to be a problem, if she was uncomfortable I’m sure she’d let me know. I just keep it in there and I’m sure one day she’ll want it on her
Mine just started using it when I changed her to a toddler bed as opposed to cot she’s had a duvet since the autumn time. It’s ironic she’s just started using it when the weather has started to get warmer 😂
I think it's just something that takes time for them to realise it's a part of their bed and sleeping arrangement. My son's only a month older and we introduced a pillow and duvet around October, and it's only recently that he's started sleeping under it. We do make a point of tucking him in when we put him to bed (and as of the last few weeks he moves his arms as though he's expecting it), and have to readjust it sometimes when he's rolled about in the night.