Britney Spears doesn't give what he wants and it makes Kevin Federline mad that he is preparing to pen a tell all book about the pop singer.

The wannabe rapper, who split from Britney last month, is reportedly prepared to write a "steamy, scandal-filled book" about his estranged wife, revealing her alleged drug use, wild partying, lesbian tendencies, plus her supposed belief in time-travel. No one could stop K-Fed from publishing the book, unless Spears gives him what he wants from their divorce settlement.

A source told America's Star magazine, "Kevin is either hoping a publisher will pay him big money for the book, or that Britney will cough up more cash than what is in their prenuptial agreement to keep him from spilling the beans."

Despite the fact that the prenuptial agreement entitles Kevin to $360,000 in spousal support and $7 million from the sale of their Malibu marital home, the wannabe rapper has applied for sole custody of the couple's two children and is reportedly seeking a settlement of at least $20 million.