Why do nipples get erect?

The biological reason for nipple erections stems from the need to breastfeed babies. Smooth muscles around the nipple plump it up during stimulation from a child to facilitate feeding. But milk doesn’t necessarily have to flow for your nipples to feel stiff. The conditioned response can also be triggered by other stimuli, like sexual arousal, cold, and fear. If you’re self-conscious about your nipples, avoid sheer bras and go for ones with thicker fabric or even a little padding.

The original nipple erections (isn't that the name of a college band?) stemmed from our need to feed our babies. Smooth muscles around the nipple plump up the nipple during stimulation from a child to facilitate breast feeding. But milk doesn't necessarily have to flow for your nipples to feel stiffer than a twice-starched oxford. The conditioned response can also occur in response to other stimuli, like sexual arousal and fear.