The current consensus is that it isn't yet currently possible to create new animations for NPCs, only overwrite existing ones. Beast races are the exception to this rule, which could end up being a workaround until Bethesda gets their heads out of their asses and patches the creation kits bugs/shortcomings. In other words, see this thread http://forums.nexusmods.com/index.php?/topic/563743-sex-mods-will-not-be-happening/ It'll happen eventually, it's just probably going to take a long while to have something as extensive as Sexlivion (never used it myself but I have enough knowledge to know it had a bit of depth)