Almost everyone knows that girls' nipples get hard when they are sexually aroused. But there's more to it than just that. And science explains us exactly why it happens. However, one question that has not been answered yet, and probably won't be either, till the end of eternity, is exactly what it means when a girl's nipples get hard, and you're with her. Anyway, knowing what causes nipples to get hard does looks like a reasonable step towards discovering what it means when they're hard, and so, we bring to you science's discovery in what follows.
Check it out!
But we all know that, don't we?
When our ancestors used to feel cold, they'd get goosebumps which would raise their fur to keep them warm. We have evolved out of the fur, of course, but the characteristics of getting goosebumps remain, and hard nipples is a part of it.
The area around the nipples - the colored area - is made up of tiny muscles which contract when stimulated. And cold too is a stimulant. So when they are stimulated, they contract and retreat backward, leaving the nipple
So what does it mean when they get hard? Well, we now know why they get hard, but to know what it means, you probably have to Google it!