...Most of the body is covered with eccrine sweat glands that secrete water and a little salt. This doesn't feed anything, and so the sweat evaporates without stinking. So far, so good. It turns out, though, that around the rest of the body there are things called apocrine sweat glands. They're just about everywhere people have thick body hair, and both the hair and the glands really get going only after puberty. These glands don't just give off water and salt. They mix in sialomucin. Mucins, as the name suggests, result in a lot of the body secretions that could be described as gelid. Sialomucin is a component in breast milk. It feeds children, when secreted by the right body part, but when secreted by the apocrine sweat glands, it feeds a lot of bacteria. The armpits are the best place on the body to get it, since they are always warm and moist, have no cleaning systems, and almost always have a free buffet.