Christian, on page 135: "I want you to become well acquainted, on first-name terms, if you will, with my favorite and most cherished part of my body. I'm very attached to this."
Given the unusual lack of explanatory prose around this bit of dialogue, I think we're supposed to take this statement straight, at face value, without self-consciously mocking undertones.
Sorry, Christian. I can't take you seriously any more. Not only do you have a HUGE CLICHE for your favorite body part, but you also use the phrase "making the beast with two backs" as a synonym for "having sex." I have never heard anyone, much less a modern, 27-year-old dude from the U.S., use this phrase, Iago excepted.
James clearly has no concept of voice and how all people — and therefore characters — have unique, individual, internally consistent ways of expressing themselves.