This one's about cunnilingus:
"Like those paperback novels where you read one story going one way and then turn the book over and upside down to read another going the other way: as you read you might finger open the pages that you'd discover later and see them upside down and backward but they wouldn't be when you went to read them. You'd just dive in.”
While this is about sex generally:
“He would come to learn – he was learning already – that these moments, different as each one was from all the others, were all more like one another than they were like any in the rest of his life: they were like the moment in some movies when a scene changes in an instant from black and white into color, and everything is the same but now this picture has become one of those rare ones that are colored, it joins that richer life, and for a time you live in it, until the gray real world comes back again."
Both passages portray sex as something that might be magical to a younger person but that, to someone older, depending on temperament, might seem tired and gimmicky, if perhaps still somewhat flecked with magic. Technically sophisticated, but still leaving one with a feeling of hollowness... a mechanical attempt to simulate transcendence.
As John Crowley says elsewhere, "You can come to the same old conclusions. What's important is the effort you make and risks you take as a writer, what it costs you to affirm the same old conclusions."