Simple when you see her on the camera reach out to her then when your asked to help her or give boundaries pick help her and then continue until she sees you in the bathroom that's he handjob scene, the next day let her get the "Memory" or whatever out of your sperm. BUT MOST IMPORTANTLY TO GET TO THIS ENDING you have to tell your friend about Malo and coming down to the end decline your friends handjob offer and it will lead to this ending where she's literally acting like a succubus draining the player dry