How come no orgasm?

First, if you are only 18 and have been with 17 partners, you may have had time to become aroused, but you have not had time to become totally comfortable with any one of these people. It takes time for a couple to fully and openly communicate their needs and preferences. You understand your own needs and are quite comfortable alone, so orgasms with masturbation will of course be easier. In addition, you have "conditioned" yourself to respond to your own touch, and it would take time for a partner to learn how it is you touch yourself and for you to learn to accept his touch as though it was your own.

If most of our partners have been teenagers, they have not had the time to gain the experience and understanding of a man who has been around a little longer. This is not a matter of the number of "scores," but rather the level of maturity and genuine concern for pleasuring a woman. It is both your responsibility to communicate your needs and your partner's obligation to fulfill them, and that takes time, patience and a genuine caring.

Oral stimulation is typically the easiest way for a lot of women to orgasm, assuming the stimulation stays on target. Although some women will climax reliably with intercourse, orgasms during intercourse (vaginal stimulation) is difficult and, in fact, impossible for the majority of women. Yes, it is estimated that only about 35% of all women have ever had an orgasm during intercourse (with vaginal stimulation alone). While there are ways to increase the possibility of an orgasm during intercourse, you should not focus on this now. Your task is to find a patient and considerate partner who is willing to learn from you what will work, and with whom you can relax enough to allow it to happen.