The term "ffx" in the context of adult content is most likely an abbreviation for "female fetish and fantasy." It refers to a genre or category of pornography that focuses on the sexual fantasies and fetishes of women, as opposed to male-centric genres such as "hardcore" or "anal." These videos often explore themes like romance, roleplaying, costumes, or other scenarios that may not involve hardcore sex but are still erotic and appealing to a female audience.