The rude answer is the one everyone says first. The riddle is built so you blush, then it turns out to be a key on a belt.
A strange thing hangs by a man’s thigh, under his cloak. There’s a hole in the front of it. It’s stiff and hard, and it has a good place to live. When the man lifts his clothes above his knee, he means to greet, with the head of the thing that hangs there, the familiar hole it has often filled before. What is it?
Give me a hintThe hint
Forget the first thing you thought of. It hangs from a belt.