Mmmmm, just thinking about the taste of those balls gets me horny.
The next thing I do is lick the bottom of his cock. Do this with two fingers, run them up and down the underside of your dick, base to tip.
I don't neglect the balls while I do this. Fondle them with your off hand just like I would.
Oh yeah, that's it. I find about three minutes of this is enough to get a guy worked up and moaning my name the way I like.