Just as erogenous zones. The most sensitive to touching is the "head" of reproductive organ, that's why it is recommended to focus on it. You can easily bring your partner to orgasm, gently touching only the this part of penis with your soft tongue.
The penis shaft (body itself) does not have sufficient sensitivity, as the testicles or head do, so the manual or oral stimulation of the zone is not going to bring to the man indescribable pleasure. You can add a lot of it in your erotic games if paying more attention to the testicles.
Try the following: take the penis with one hand and gently lick all the lower part, then in length from the bottom - up. When you reach the glans, gently gently brass it with your mouth. Depending on the reaction, you will see what part of the male genitals are the most sensitive and gives your lover the greatest pleasure. Learn to manage the length of the love games - control the ejaculation.
Also have a look at Guides to a better sex, you better know what you like.
