Play through the game as normal. When you're taken to the Cult of Ecstasy mansion for the first time, you will wake up to Mabel. Choose any of the options then go through and talk to Sabinian and Lily, then get the pills for Christopher. After that, go up to the second floor and talk to Mabel again. Choose any of the cards, then tell her, "I don't believe in Tarot."

Play through the game as normal again until you return to the mansion after Johnathan kills Lily. Join the orgy, go to Theodore's room and get the diagram and open the box, then let Mabel talk to you. Tell her, "You can trust me," then go back to Lusstgha with Amanda and have sex with her. When you return, talk to her again, then go join Mabel in the attic. There, she will ask if you trust Amanda; tell her "no," then tell her "yes," you think about Lily "all the time."

Enjoy! :D



Credits: MaxFB for finding the correct dialogue choices.