There was an article in the Guardian today about a cache of English erotica held by the British Library -
British Library's Collection of Obscene Writing Goes Online They mention a book called Teleny or Reverse of the Medal, one of the earliest works of male gay erotic fiction. I wonder if PO'B was aware of the book or the title of his novel really was just the accepted meaning of the term, an opposite and usually less favorable aspect of an affair or question.