first yellow star: play through as normal, at least lose at the card game or don’t answer all of shadow milk’s questions right, or don’t get the book for pure vanilla. Any will work, but you have to have them both together. Then you give them the berry juice. Second yellow star: Truthlesssage ending, hide shamil in the bedroom, let him come with you to townsquare, and let pure vanilla sleep together with you. That’s all!