These days I am 42B Cup and thankfully Marks & Spencer di a range of very comfy cotton and lace bras down to 42A. However my favourites are a couple of padded push up bras and pantie sets from my favourite lingerie supplier Simone Perlele (the French Lingerie manufacturer). I also own a few items of beautiful lingerie from them, but I really like their matching bra and panty sets (although I prefer wearing a G-String or Thong)
However when I was just a A cup, I always wore Playtex Cross your heart bras with Amoena Breast inserts . They are supplied for mastectomy victims so are incredibly realistic but expensive. However these days my breasts jiggle too much without wearing a bra and my nipples are very obvious as they are always extended (my aureola are quite large too, so I cannot wear tight white T Shirts any longer without a cotton bra underneath as they are just too obvious).
So these days its a bra all day, except in the shower. One thing that I have noticed is that at night tome these days my nipples are starting to leak a bit, so my Nurse Practioner has recommended that I consider wearing a cotton bra when I am sleeping too, as she felt it was important to support the breast tissue as I am now growing them substantially. I should say that I have quite a lot of breast tissue now to the sides from my armpits towards the nipples.