A line famous from Notorious B.I.G's single "Get Money". "Fuck a bitch shit" refers to the act of not giving a fuck, having no consideration, and simply not caring about a bitch/girl/hoe.
"Because of you I'm on some real fuck a bitch shit."
An actual song title by A Tribe Called Quest. "Bonita Applebum" refers to a woman/lady/girl with a nice ass, or simply refers to a nice booty (usually a large/round apple-shaped one!)
"Hey, Check her out, she's got a bonita applebum."