For sexually precocious boys, half have an orgasm by the age of 7 and two-thirds by the age of 12. But until they start ejaculating, such orgasms are one-offs or sporadic. Most boys (90%) ejaculate for the first time between the ages of 11 and 15. The average white male has his first orgasm that leads to ejaculation by the age of 13 years 10½ months (13.88 years).
Ejaculation (of semen) and male orgasm are two separate phenomena. It is possible for a young boy to orgasm without ejaculating. But once a boy reaches adolescence (assumed to coincide very approximately with his first ejaculation) he most normally ejaculates every time he has an orgasm.
Some men believe that ejaculation is possible without a preceding orgasm but they are confusing orgasm with the concept of orgasmic pleasure.
Ejaculation does not involve mind-blowing pleasure every single time because the sensations that accompany orgasm inevitably vary. We feel varying degrees of sexual pleasure depending on the physical and psychological (erotic or emotional) circumstances that give rise to orgasm. There is no physiological event other than orgasm that could trigger ejaculation.[i]
Some male prostitutes climax five, six or more times per day regularly over many years. Even with such high frequencies, although the quantity of ejaculate is lower than usual, a little semen is always produced. Around three quarters of men do not ejaculate with any force. Their semen is merely exuded from the glans. Other men may ejaculate semen over distances of a few inches or even a few feet (rarely up to more than a meter!).
Biological changes to our bodies that are beyond our conscious control attract our curiosity. Women can be fascinated with the changes in their bodies during pregnancy just as boys can be fascinated with their penis during puberty (and beyond!). At puberty girls get breasts and periods: body changes linked to their child-bearing role. Few girls focus on masturbation as boys do. The male arousal cycle explains the difference. Boys are fascinated with their responses but girls experience nothing equivalent.
A man takes pride in his ability to achieve an erection. He enjoys not only the sensations of his physical and mental arousal but also the pleasure of being physically stimulated (even by himself) when erect. The visual evidence of his erection adds to a man’s sexual arousal. Consequently men (unlike women) like to observe their genitals as they stimulate themselves to orgasm. A man is aroused by what he sees and by objects associated with sexual activity. His own erection is simply one of those associations.
[i] … it is difficult to understand what mechanisms could produce ejaculation without a precedent orgasm. The confusion in the literature seems to be the result of making the term orgasm and orgastic pleasure synonymous. … there are admittedly occasions when there is little pleasure accompanying an ejaculation. (Alfred Kinsey)
Excerpt from Sexuality & Sexual Techniques (ISBN 978-0956-894724)