I'd do it with this gold id bracelet from laura lobdell (filed under "five easy pieces").
The silver guitar pick is pretty rad too. But promise you won't give it to him unless he knows his way around a guitar.
Wait.... Now I'm confused. Would it be cooler if he's never been anywhere near a guitar? You tell me.
*Not that I would want to go back and change the messy, spontaneous way it happened.