This sleep and leisure bra by Fancee Free is so comfortable! Made out of 100% cotton knit with double layered front cups which overlap at center. You will forget you have a bra on, it is so comfortable! Designed as a sleep bra, nursing mothers have long pre-empted this bra for their own. Cups can pull down to nurse (no attachment to fiddle with).
When I bought it I was a 42 DD so it will definitely fit a 40. It wears like a sports bra so there is no adjusting.