Leon Wieseltier, believe it or not, introduced me to this samizdat Auden masterpiece. New York Magazine has unearthed it and I was reacquainted with it via Chris Orr. It's a Hitch fave too. You can read the whole thing here, but this is how it starts:
It was a spring day, a day for a lay, when the air
Smelled like a locker-room, a day to blow or get blown;
Returning from lunch I turned my corner and there
On a near-by stoop I saw him standing alone.
I glanced as I advanced...
It's now past St Patrick's Day and the sap is rising.