It depends on your relation with them, their dicks will only show when you have it high enough
Not really. It depends on your beast_lover status which is hidden. Your relation doesn't matter at all. To get beast_lover points you need to do lust scenes with beasts. You may need to do this 20 or more times until the functions related to beast_lover available. Keep in mind that violently winning against beasts decreases the beast_lover score and will lock all options again if you do that too much.