They can even change colour... 

From breast-feeding to piercings, your nipples can be used for a number of different things, and here are just a few more facts that you might not have known about them. _________________________________________ Orgasm fun Your nipples can cause you to have a pretty amazing orgasm. It’s all to do with your brain releasing oxytocin when they are paid a bit of attention. A similar response can happen for men too. Getting a piercing Nipple piercings can take anywhere between three to six months to heal – and for some, it can be even longer. Ouch. You can have three Six percent of people have a third nipple. One man was reported as having seven nipples back in 2012 according to the Indian Journal of Human Genetics. There are different kinds There are four different kinds of nipples: normal, flat, puffy and inverted. Inverted nipples are fairly common too, as about 10 to 20 per cent of women have them. And they can have hair A large percentage of women have hair on their nipples so don't worry - it's normal. Strong nipples? Make a career out of it – just like Sage Werbock or rather ‘The Great Nippulini’ who became famous for pulling objects with his nipples. https://youtu.be/PcZSIzRCFKY They might not be identical Just as you can have one boob bigger than the other, your nipples can also be different sizes. All the colours! Your nipples can also change colours, particularly after pregnancy and even just as a result of birth control.  Video via YouTube/Guinness World Records.