First start with teasing, licking the length of the shaft and head. Get some spit together and spit on his dick or use a nice flavored lube. I love ID Juicy Lube Watermelon that I order online but you can find a decent selection at any drugstore. Run your mouth sideways up and down the shaft. Very, very gently lick his balls or tickle them with your fingers. This is a time for big ice cream cone licks and just closing your lips around the head while you lick it all over.