Do It Somewhere Daring
Getting oral sex while driving fast along a highway in a convertible (car: red, girl: blonde) is a typical teenage boy's fantasy. But when you're younger, you tend not to think things like "If he's having an orgasm, he's not exactly paying attention to driving" or "This could be fun but could also kill us." Therefore, a lesser '- but no less appealing '- version of this is to casually reach across the car, unzip and expose him, then dispense a leisurely hand job that keeps him standing at attention but doesn't bring him to climax. Shift to using your mouth when you arrive at your destination. Other places to go down on him that are daring but a little less so: in the bathroom at a party, on a balcony with his top half in view but you hidden, and up against the front door inside your apartment when he was previously on his way out the door to work.
Lick It Like It's a Lollipop
This one is often used in porn films, because it allows him to see exactly what's going on. It's best done on your knees, and depending on your heights he might need to stand on something (you need direct access to his testicles). Start by lifting his penis to expose his testicles, then find the line that runs up between them (it's a tiny ridge that's often a darker color). Find where this starts on the underside of his testicles, and that's where the long lick starts '- continuing, very slowly, right to the tip of his penis. Repeat the full-length licks until you've done at least 10, then move into one of the other techniques.