STYLETHREAD -- LET'S TALK SHOP!

Weird I know and my husband thinks this is hilarious but use surgical tape or "garment" tape. Just enough to lift a bit and not bounce around. I use one piece on each boob over the ni**le. TIP- put a little vaseline or other lotion right on the ni**le - can be a bit painful when you take the tape off.

I do this all of the time and I am a 34C - holds like a champ.

This is what I use for those formal dresses that need a bit of lift but don't cover a bra.  It is also surgical tape, stays put, and doesn't hurt to remove.
http://www.wonderfulbuys.ca/bringitup.asp

They are sold at a few places and there are re-usable versions as well as disposable ones.