You can stay the night at Bernard's and have sex after a bit of talking. The scene lets you top or bottom without changing ur character's top or bottom trait as well as choosing human Bernard or werewolf Bernard. This happens after the werewolf storyline is done and with high enough affection
you do the werewolf storyline until after you choose bernard or logan, you should get a prompt about the witch and after talking to her she has a quest that unlocks the wolves den.
However with the witch some of her content is only unlocked at day or night so if it's not there for some reason wait till it's the opposite in game time.