ick. It's not the nipple. bleh bleh bleh. It's all that sensitive skin area on the actual breast itself. I have some beautiful scars (>_<) on my boobs from some of the bandaids I've used to cover the nipples. Hubby was not happy about the scars. One of the scars look like someone bit me. V^^^V
But if you use bandaids, use the GENTLE CARE ones. Not comfort, not sports, not waterproof or what have you.
I suppose I could try to find some cosplay that could work that in, but, who...hmmm.
*Imagine's Didjiman in a skirt along with Karisu's manly unchest*