I hope a DM I know never reads this, because I know he'd absolutely want to use this idea.I guess this has been topic when discussing human sexuality: Enslavement by sex. So following the though, can't there be a group of (most probably female) "sexforged" that keeps a band of (then male.. at least mostly) humanoids under control by sex? But maybe that'll be too perverted, even for fantasy role playing games.