Anyone know if there anything specific to trigger the threesome scene with Isabella and your dad? Ive tried talking to him in his office on Thursdays and other days but I never get the the option. Was it something I was supposed to do before actually seeing her in the hotel for the first time?
EDIT: Figured it out. Need to progress Dad enough that you agree to share Anna, you then get the option to talk to dad about isabella.
Also, just saw Dad can join you with river on Friday (not sure if that only applies with the slut route though).