Why do your nipples get hard when you get cold??
When it's cold the skin of your nipples contract to decrease overall surface area and better conserve heat.
site:http://www.associatedcontent.com/article/2210465/whynipplesgethardinthecold.html?cat=52
they also go hard or erect when you are aroused its normal and its just part of what the human body does
how does that work?? how does your nipples getting hard keep the heat in??
To keep heat in. x