My DTs are 17 months and 'average' sleepers (lots of kids seem better than them but the lack of sleep is manageable!).
They tend to have their nap in the cot in sleeping bags as well as night time. However, every now and again they fall asleep in the pushchair and it's safest to transfer them to cots and just put a sheet over them. I can't be sure but DTD seems to nap better under a sheet than in a bag. Just curious if anyone else found their toddlers were happier in sheets or possibly even a duvet at this age? Thanks.