John Kenney in The New Yorker:
And I’m not alone in history.
Teddy Roosevelt, for instance, was a big fan of photographing his penis, and would pose for hours at a time. In Paris, in the twenties, it was all the rage. Hemingway’s little-known short story “Look at This Photo of My Penis” attests to it. Stalin often adorned his dacha with framed eight-by-tens, coyly saying to visitors, “Boy-oh-boy, is that a lovely penis, or what?” (The wrong answer proved costly).
Go back further, of course, and you’ll find the drawings. Jefferson was a madman for it, often sending John Adams dozens of sketches of his penis in a single day. Adams is said to have enjoyed them with his wife, Abigail, who was herself a fan of penis portraiture. Even further back, we find that Michelangelo, Raphael, and Titian all made frequent charcoal sketches of their penises, giving them as gifts (a common practice in Florence to this day). And then there are the famous cave drawings at Lascaux, France, purported to be more than seventeen thousand years old, where one sees dozens of penis portraits, crudely drawn, but a statement in their own right: a plea, as if to say, one cave man to another, “My name is Dave. This is my penis. Let us be friends.”