Are you talking about FFM threesomes? They should be unlocked, like all other events which need some "grinding" in the original game.
Just so you know, there are no new animations provided by any mod. Mods concern appearance (tatoos, hair, clothes/accessories, eyelashes, etc.) technical features such as lightning, some playability features such as boob wiggling or whatever its called. One mod unlocks all possible animations at once, regardless of the female character's attitude towards you, but do not add more animations.