Yes you can pierce a nipple but remember that Body piercing should be performed by a qualified piercer in a clean sterile environment.
You do not want to do damage to your body or risk infection so seek the expertize of a fully trained and qualified piercer. Also read up on the risks of piercing your nipples and if you are pregnant or are thinking of getting pregnant. Elayne Angel has a great book on this called the piercing Bible.
If you are pregnant DO NOT get pierced anywhere your hormones are changing to rapidly.
That can vary from male to female.
A properly placed nipple piercing goes halfway down the nipple. You DO NOT pierce the areola, nor do you pierce close to the tip. Of course, this rationale is for normally sized nipples, because unfortunately some piercers pierce nipples that were never meant to be pierced. Go to a professional and have them evaluate it for you.
Nipple piercing is not only for the look of the piercing but also for personal stimulation, once healed nipple piercings can be quite erotic and will add sensation when the right jewellery is in the piercings.
If the nipple is large enough, then it is possible to pierce one nipple twice in the same direction. I would suggest you talk to your local professional body piercer, they can have a look and tell you if there is enough tissue to support a second piercing.
No
Until a woman is 18, it is illegal for a shop to do a nipple piercing on her. For men it's not illegal as far as I know, but most piercing studios will not pierce someone under 16, others may refuse to do nipple piercings on a male under 18.
Definitely 18. Depending on state, you can get your ear pierced at 16 without consent and other places with, but no piercer can pierce a minor's nipples regardless of consent.
A nipple is a nipple, simple as that. The sometimes darker // pinker skin around the nipple is called the aureole.
The nipple is lateral to the sternum.
nipple bras.
You can't, & any place willing to pierce you underage isn't someplace you should be willing to trust. They're already displaying no regard for the law. How sure can you be that they don't reuse needles?
Yes, each normal nipple has multiple openings.