Callie: If you've been having threesomes with her and she doesn't invite you to make it a permanent thing with the option to visit her house as a night option, you need to either have more threesomes (I think three are required? maybe 4), or you need to upgrade her opinion of you.
Upgrade her opinion by asking for more fashion shows/working for her more. Work: I'm not sure if doing a day long double shift for her is required, but it definitely helps. Fashion shows: make sure you've seen every possible outfit at least once (the first outfit, the hunting outfit, the underwear, and the leather outfit), and ask for nude shows until the content there starts to repeat (4-5 times, I think). One last thing that could be holding her back from making the night time invite: after the first threesome, she wants to talk to you about it. If, after the first threesome, you never visited her shop to let her talk to you, that could be the thing that's holding her back from making the nighttime invite.
Primrose: in the gallery, the bottom row of her scenes are 1, if you got an offer of romance from Primrose and accepted (missionary position), and 2, if you got an offer of FWB from her and accepted (doggie style). The top row of scenes are: boob job, cunnilingus, and fellatio.