Jackie Book
A book written for a mature audience. This type of book usually has sex scenes and other content that would be inappropriate for younger readers. This is a term used to cover up the fact you are reading a "naughty book".
A: This is such a great book!
B: What's it about?
A: Oh, you know, its a jackie book
B: What's it about?
A: Oh, you know, its a jackie book