Yep, just the one. You can also add other fetishes to the elixir, obviously, and choose between physical and behavioral fetishes. I myself usually put the incest, pregnancy, pussy slut and cock addict fetish in mine. It's important to learn how to force the characters to do the things you want them to, and the best way to go about it is with the Fetish Endowment. Keep in mind you can also use the endowment to remove fetishes you don't like from a character, and, take it from me, use the save button in the enchanting screen if you think that you'd like to use the enchant more than once, so you can come back and just load it in with the click of a button.