Why breasts "erection?"

Why breasts "erection?" Q : life, I will often encounter the "embarrassment" of the scene will baffling nipple erect tall. Whenever such times, it seems like I did not wear the same Bra. Although I do feel that her husband no, but I still hope that they would "calm down". I would like to ask : how should I do? A : Under normal circumstances, nipples erect is Xinghuanqi results. But Xinghuanqi nipple is not "erectile" a sign. Erect nipples or not, and personal health, there is essentially no way to change. You can wear a thick filler Bra, so nipple can safely hide. If you do not want to make it too big chest, it may be in each cup stuffing a thin layer of sponge, or the nipple stickers affixed milk.