Cliff Booth: Hey! You're Rick fucking Dalton, don't you forget it.
Cliff Booth: Eh... You are?
Tex: I'm the Devil, and I'm here to do the Devil's work.
Cliff: Nah... It was dumber than that, something like Rex.
Katie: Shoot him, Tex!
Cliff Booth: Tex!
Bruce Lee: My hands are registered as lethal weapons. We get into a fight, I accidentally kill you? I go to jail.
Cliff Booth: Anybody accidentally kills anybody in a fight, they go to jail. It's called manslaughter.
Cliff Booth: And away we go.
Narrator: When you come to the end of the line, with a buddy who is more than a brother and a little less than a wife, getting blind drunk together is really the only way to say farewell.
Cliff Booth: Don't cry in front of the Mexicans.
Jay Sebring: Is everyone okay?
Rick Dalton: Well... the fuckin' hippies aren't. That's for goddamn sure.
Cliff Booth: Alright, What's the matter partner?
Rick Dalton: It's official old buddy, I'm a has been.
Answer: To put some context into the scene, three members of the Manson family (Tex included) have broken into Rick Dalton's house and are holding Cliff Booth at gunpoint. Cliff, who is high on drugs asks "Are you real", to which Tex replies "I'm as real as a donut, mother fucker." Tex was trying to answer Cliff's question stating whether or not he was real, but in the most intimidating way possible, and I guess donut was the word that came to mind that described how real he was.
Casual Person