I honestly believe there is absolutely nothing like going to bed with a good book. Or a friend who's read one.

The joke works by setting up an earnest, almost genteel sentiment—there’s “nothing like” going to bed with a good book—then revealing an alternative meaning of “going to bed with,” shifting from reading to intimacy. The add-on, “Or a friend who’s read one,” extends the innuendo while also poking fun at the social cachet of books: the “friend” can supply the benefits of culture secondhand. It’s a compact example of Diller’s comic method: she uses conventional respectability as a foil, then punctures it with sexual frankness and a sly jab at pretension.