we have a few baby sleeping bags that nat's mum bought us and i haven't used them yet because i don't know how to the ones i've got are made of the same material as babygrows and vests, so are quite thin, not fleecy or anything. think they are from either tesco or asda.. basically... what should he wear underneath it?! a vest? a vest and a babygrow? and do i put a blanket over him still? his room is an average temp of 21. i just don't want him to overheat and not be able to do anything about it cos he's stuck in it..