Tell him about the book

"I know, I want you to tell me your most valuable secret, what you would not tell anyone" The reply came though. John tried his best to think, he didn't even know what to tell BlackMaster. He didn't have many secrets, that he secretly liked his best friend, that he once fantasized about my mom, and the most important thing is the book.
"I have a magic book that can make all my fantasies come true" he replied. This seemed to be a bad move.
"Don't be stupid bitch, magic isn't real! You really don't value your dignity do you?" It was a mocking tone and John grew defensive!
"Its true I swear! I can do anything!"

"if it's true you queer, I should have a wish" In the moment it seemed very reasonable to John for reasons he couldn't quite explain. he could only respond with a submissive "Yes sir"... What harm could giving this BlackMaster one wish do?