Rainbow Dash comes across a hypnosis kit, and uses it to turn Rarity into a fetish slave, to satisfy her fetishes. Done by request.
Contains: Hypnosis (obviously), fart, watersports, buttplay, and facesitting. With some mud.
As usual with my stories: Do not take too seriously. All it is is for fetish fuel for those with the fetishes (or else if they just find them funny), so don't expect much else from it. I know Rainbow Dash wouldn't actually do that to Rarity, but again this was by request, plus there are other stories like that here.
Also, the same person requested a similar story of someone else so I'll try to make this one as different as possible. (I do use different fetishes)