Not enough support. If you just don't want your nipples to show through just put band-aids over them. That will keep you from showing them to the world. Thats a little pageant advice. If you do get a backless bra make sure it is stuck on really good. You don't want to lose one of those bad boys!
Hey, I noticed that some of y'all offered to PM guidelines of how to apply the duct tape concept. I wear 32 DD and as it is, it is impossible for me to find supportive bra, let ALONE a strapless or backless one. PLEASE PLEASE PM me for instructions on how to do the tape thing. i tried it once, but needless to say, it was a TOTAL disaster.