How do i progress with the aunt? I'm already fucking everyone but her, all I can do is train with her in the mornings and nothing else.
You need to tent the private/alternate room from the hotel manager. Then when you talk to Kate (Aunt), select Requests, then About her sleeping space, then Offer your personal motel room. You will automatically give her the spare key and she will be in the room at 20:00. There are several new events in the room, but still no sex. Be warned that it's A LOT of work because she will leave the key in the room the next morning and you have to go get before you can offer the room, and no matter what, you still have to offer the room to her every day even if she stays several days and even if you've rented the room for several days. It's easiest to check by the pool every day at 16:00. If she's there, offer the room to her, then go to the room after dinner at 20:00.