Really strong mints like Altoids are fucking awesome. One of my civvie FWB's does this. She gives good sloppy head making sure there is plenty of spit running down on my balls. She'll even spread it out on my balls while massaging them. I don't feel the coolness from the mints until the air hits it so as she is sucking my cock I feel warmth of her mouth on my cock but the spit is running down on my balls will be cool. Then she'll spend a little time licking and sucking my balls clean which will be warm while my cock is getting the cool sensation. The back and forth is incredible. It helps her take it all down the hatch too.

Otherwise, make me believe you like it as much as you say you do and we're already over halfway there. Don't forget the balls. Finish it with NQNS and I'm a happy camper.
If you're a spitter then I'd rather you just slow stroke it out of me by hand somewhere else, your face or your tits. Wherever I finish will be fine just don't quit until it's time to quit. Which brings me to...

Know when to lighten up, this is critical. You can fuck up the best bj in the world by staying on it too long. 3 or 4 seconds after that last rope the glans gets sensitive as fuck. If you keep up with the pressure or sucking there it gets irritating. Light stroking or licking the shaft, licking or kissing the frenulum are all fine just stay away from the glans. Even going back down on it is fine, just don't suck. Ball massage is good too. Then let me know how much you enjoyed it!