How we cite our quotes: (Paragraph)
Quote #1
"The nights are going to be pretty long from now on. I mean. I mean—well, it starts getting dark early." (18)
Obviously, this is a reference to sex—he clearly doesn't mean that the nights are going to get long because it "starts getting dark early." That would be pointlessly redundant. He means they are going to be up longer, "making the beast with two backs" (to quote Othello).
Quote #2
"Goodness, I don't see how people do it every day."
"Do what?" he said.
"Get married," she said. "When you think of all the people, all over the world, getting married just as if it was nothing. Chinese people and everybody. Just as if it wasn't anything."
"Well, let's not worry about people all over the world," he said. "Let's don't think about a lot of Chinese. We've got something better to think about. I mean. I mean—well, what do we care about them?" (19-22)
The blushing bride is essentially mind-blown by the fact that everyone does it. What she's talking about is sex, of course, but she uses the genteel shorthand of "getting married." This is kind of like the Cole Porter song that states "Let's do it… let's fall in love." Falling in love is not what that song is about, btw.
Quote #3
"I know," she said. "But I just sort of got to thinking of them, all of them, all over everywhere, doing it all the time. At least, I mean—getting married, you know. And it's well, it's sort of such a big thing to do, it makes you feel queer. You think of them, all of them, all doing it just like it wasn't anything. And how does anybody know what's going to happen next?" (23)
The fact that the wife says "I mean" shows that—like the husband—she's thinking about sex as well as marriage. The phrase "I mean" has the same symbolism in this story as a sock on a dorm room door… it means sexytimes (or at least the thought of sexytimes) is happening.