This is a call to begin kissing your books upon completion. Why this odd request? I found it in the book “In Praise of Good Bookstores” by Jeff Deutsch and thought it would be a fine way to show respect for what we read:
These books were read—books are for use, after all—and were treated with reverence and love. Observant Jews are accustomed to kissing the cover of a book after closing it—a habit that has remained with me throughout the years.