There are at least three different things I know of that fall under that heading. Two of them are Wiccan traditions, and I know very little about any form of Wicca; it never really interested me. The third -- well, traditional lore has it that the best thing to do with the fae is leave them strictly alone. They hate and fear humans, with very good reason, and they tend to mess with people who try to make use of them. I really don't recommend it.