Nipples

Hehehe, you know ;). Those little things that mammals have that erm...how do I put this? They make milk. Like cows have them to make milk and so do the other mammals like us. Unless you're not a mammal. Yes even cats and dogs have them! They can also be a sexual thing for some people so that's interesting. A lot of animals actually have more than two! Usually an even number in a symmetrical pattern. Not really sure when they were invented but they've been around a while. It's also the word for something in plumbing parts? Anyway no I'm not gonna add a picture, weirdo.