I've seen common Blackmail elements in F/M fantasy stories. Usually in cuckold stories. But not really my thing. Looking for a similar FF only story. Ideally in the "beautiful people universe"(both girls - nifty tends to have some butch themes lately, so its hard to find what I want), where one girl is "hetero", and slowly converted to preferring the touch of a woman. Maybe the aggressor is more about molesting and seducing the victim. And ensuring the victim always gets strong cums, or cum denials. I'm pretty flexible. Cryptkeeper on asstr had similar themes, but only once briefly touched a FF only story. 99.99999% of it was cuckold. Dawn1958 also had similar themes, but again, too much cuckold/penis scenes for my liking (even though it had common element of the hetero girl falling/getting bent, but for whatever reason a common element was to have her bang a younger dude in a group scenario to complete her corruption).
Any combination of F/F f/f, F/f will do. Not really in it for g/F, but willing to give it a try if it's good.