They kept their secret from the knowledge of others, not as a shameful guilt, but as a thing that was immaculately theirs, beyond anyone's right of debate or appraisal. She knew the general doctrine on sex, held by people in one form or another, the doctrine that sex was an ugly weakness of man's lower nature, to be condoned regretfully. She experienced an emotion of chastity that made her shrink not from the desires of her body, but from any contact with the minds who held this doctrine. (184.108.40.206)
Like so many concepts in the novel, sexual morals have to be translated and flipped around in the Objectivist value system. So Dagny, fittingly, experiences "chastity" not in regard to sex itself but in regard to the people who preach that sex is ugly and sinful.
The course led them to the moment when, in answer to the highest of one's values, in an admiration not to be expressed by any other form of tribute, one's spirit makes one's body become the tribute.... (220.127.116.11)
The style here is interesting – the scene begins by discussing Francisco and Dagny, but the style shifts from "them" to "one," which emphasizes the broader, philosophical statement the passage makes. This sort of style shift, from specific character to broad ideas, happens a lot in the novel.
"What I feel for you is contempt. But it's nothing compared to the contempt I feel for myself. I don't love you. I've never loved anyone. I wanted you from the first moment I saw you. I wanted you as one wants a whore – for the same reason and purpose." (18.104.22.168)
Hank parrots society's ideas about sex to Dagny, even though his actions and his deep feelings for her ironically undermine everything he is saying. This shows how influential society's moral code is and how hard it is to break free from. (This also wins the award for being the worst morning-after speech in history.)
"The man who is proudly certain of his own value, will want the highest type of woman he can find, the woman he admires...because only the possession of a heroine will give him the sense of achievement, not the possession of a brainless slut....He does not seek to gain his value, he seeks to express it. There is no conflict between the standards of his mind and the desires of his body." (22.214.171.124)
Francisco's Sex Talk is the most important thematic statement about sex in the novel. Francisco explains that sex, in an Objectivist value system, is about the individual and reflects a person's values and self-esteem. An individual living for his own happiness will treat sex as a good thing and will only have sex with someone he loves.
He did not know it, he did not think of it, he was past the need of words, but in the moment when he felt the response of her body to his, he felt also the unadmitted knowledge that that which he had called her depravity was her highest virtue – this capacity of hers to feel the joy of being, as he felt it. (126.96.36.199)
Hank highlights the theme of switching word meanings around again when he realizes that what society calls "depravity" is really a "virtue." It's also interesting that Hank is described as "beyond words" here; this happens to various characters in the novel and emphasizes the depth of feeling our heroes, whom the looters often call "unemotional," have.
"No matter what happens in the future, we'll always be what we were to each other, you and I, because you'll always love me."..."Will I want to sleep with you? Desperately. Will I envy the man who does? Sure. But what does that matter? It's so much – just to have you here, to love you and to be alive." (188.8.131.52-3)
It's interesting that Francisco unites his past, present, and future with Dagny here, noting that their bond won't ever break, even though the nature of it will change. Sex here is just one way to express one's love.
She lay on her back, her palms pressed to the sheet at her sides, to stop herself from rising and walking into his room, knowing that she was capable even of that.... (184.108.40.206)
This is one of the few scenes where Dagny seems almost out of control. Her fight against her desire for John is interesting, since she would argue that sexual desires shouldn't be ignored.
"For two years, I had been Hank Rearden's mistress. Let there be no misunderstanding about it: I am saying this, not as a shameful confession, but with the highest sense of pride." (220.127.116.11)
It makes sense that Dagny, whose values are the opposite of those of society, would consider being a "mistress" something to be proud of.
He jerked her closer, to stifle the sight of his own shudder. His hands were going through the automatic motions of intimacy – and she complied, but in a manner that made him feel as if the beats of her arteries under his touch were snickering giggles. (18.104.22.168)
The awkward and spiteful sex scene between James and Lillian greatly contrasts to the scenes we get with Dagny and her various lovers. The diction, or word choice, is telling here: James is described as using "automatic motions," while Lillian seems to be "snickering."
[I]t contained her pride in herself and that it should be she whom he had chosen as his mirror, that it should be her body which was now giving him the sum of his existence, as his body was giving her the sum of hers. (22.214.171.124)
The use of the word "mirror" suggests how sex is viewed in Galt's Objectivist value system. When sex is an expression of love and values, a person's lover becomes a "mirror" for those values.