1) Firstly a perfect BJ combines a perfect HJ with it
2) Slow, Prolong - Dont let him cum that soon. Make him damn desperate to cum
3) Use your hands (yes plural)
4) Vary the rythm, depth, angle (use hands as well, example twist it) - variation = surprise. Dont make it monotonous and predicatble
5) don't stop when he cums. Once squirts are over, restart for a few more strokes. He will twitch. Enjoy that.
If you are not 'silent during sex' type, the communicate...
One of the best BJ clip I had ever seen is here
Amazing Blowjob
I still wonder how he could hold that long
I sincerely appreciate your interest
Good luck