I was thinking how odd it was: endless ingenuity has been spent developing bidding systems, to the point where if you play bridge with a new partner you always start with a conversation where you ask whether they play Acol, Standard American, Precision or some other system, and where, if you're playing a natural system, you ask whether they use standard conventions (Stayman, Blackwood), whether you will play weak or strong no trump, weak jump overcalls, what system of discards you'll use, and much more. If you play duplicate, everyone has to fill out a preprinted (!) card setting out the conventions they play for the benefit of opponents. The hanky code is the closest thing to this that I've heard of in the sexual realm, but a) it was always pretty simple and b) I'm told it is now passé. For the most part, the rules for communication never get past NO MEANS NO and YES MEANS YES.
Anyway, I thought about this as the basis for a book, and sometimes talked about the book, and most people (not, perhaps, being bridge players) looked at me no so much with wild surmise as with blank incomprehension. But I went to New York several years ago and had dinner with Dale Peck and began talking about bridge and sexual codes, and Dale understood instantly! Dale had willfully revived the hanky code in his youth; Dale had been a fanatical bridge player; we talked and talked.
Dale is now editor of the Evergreen Review, an online magazine, and he has published "Sexual Codes of the Europeans: a Preliminary Report" in the latest issue. It's here.