I don't know if 1.8 changed some things, but the guide says this:
- After groping Anna enough and taking some pics at the studio with your cock you will trigger a scene where she loses control during the photoshoot and starts to suck you off. This will get Anna to 4 hearts. (After this, you will progressively unlock the sex scene with Anna.)
- Upon Anna reaching 4 hearts you will receive mail for Starcon. You can select Starcon on the weekend trips menu.
- After asking progressively for titjob and handjob in the basement and groping some more, the subsequent visit to the basement will trigger the 5 heart event where she asks to have sex and will automatically pick a route based on the amount of corruption/romance points (The route chosen does not affect any interaction/ route of other NPC the game. Anna will change her outfit in the Kitchen depending on your choice. Route affects the scenes shown at the park [3 for each route]. Slut route also allows better fan service at Starcon)