Forgive the intimacy of the following revelation; the revelation matters.
When Mr. Fallen and I would have sex, he would make no noise - except, just at the end, I could tell he was about to have an orgasm because he would say, "Oh! oh! oh!" It wasn't like, "Ah" or even an open "oh": the sounds were round and fully formed, and to be strictly accurate they were more "O! o! o!": I thought of them as little bubbles of O. It was very precise, and for that reason very striking.
I see now that that pronunciation makes the utterance very heartfelt, for when I contemplate saying good-bye to all these people, then getting on the plane and being without them, suddenly and completely and for a long time, I say aloud to myself, "O. O. O." Only this captures the precise slice of the pain, and the terrible clarity of the sense of loss. O. O. O.