The same way you make a guy's nipples hard.
Impossible
Ice them
To make your nipples hard, you need to sexually stimulate yourself. Massage your boobs, rub them, squeeze them, etc. Also, flick, lick, and touch your nipples as much as possible. Your nipples will get hard once you're horny and sexually stimulated.
Maybe if used externally.
If you want to make her nipples hard play with them use the tip of your tongue around her orioles or a piece of ice and for sure they'll get hard
Nipples that are really hard are referred to as being taut. They can also be called stiff or hard.
no, if u r cold your nipples tend to get hard. Women will most always get hard nipples when aroused and most men wont, but some do. if u r Mae and get hard nipples when aroused it doesnt mean theres anything wrong it just happens.
Yes, they do.
Hard.
Genetics,,, I once had A girlfriend that had nipples that were undetectable without your eyes.
We don't. They get hard when it's cold or some women get hard nipples when they are aroused. Same reasons some men have it actually.