I did some test runs of the game, and here's what I found out, though I'm not sure if there are more than these.
1. If her 2D animation sprite comes out, keep patting here until the sprite disappears.
2. Pay attention to her facial expression around the room. (Normal, Smiling, Pouting)
3. To trigger sex scenes with her, make sure she is happy for the day, aka smiling. Wake her up by touching her body parts until she wakes up.
4. Pay attention to her tone once she wakes up, depending on your own playthrough as it can affect her mood on the next day. You can easily get happy sex if she's happy before she goes to sleep.
(Might need some info on what does pouting means)