It sounds simple but it's reality.....get a higher taste by seriously following the process of sadhana bhakti given to us by Srila Prabhupada....by getting a higher taste we lose interest in the lower taste.
Thinking ... feeling ... willing ... doing. That's how it goes.
It is very difficult to retain the semen when a man thinks about sex often. First the thought comes, and if one dwells upon it for even a moment, then the mind creates an expectation of mental enjoyment in relation to the object of one's fantasies. Desire naturally arises from this, which often cannot be fulfilled due to social and other considerations. During this process, which develops from the mental to the physical, the seminal components are being drawn from the body and stored in the testes. As the semen accumulates, it becomes increasingly difficult to retain, and will eventually cause severe discomfort (congestive prostatitis http://www.straightdope.com/classics/a2_195b.html). The mind will conjure fantasies just to release the semen, if need be.
If one wants to control one's sexual activities, it is most helpful to control one's thoughts. If a man is heterosexual, he should not think of women sexually. One must be vigilant over the mind, and when undesirable thoughts arise, they should not be entertained. Otherwise retaining the semen will be virtually impossible. The body acts in reaction to the mind. If the mind is controlled, the control of the body will follow. This may seem to take incredible willpower in the beginning, but day-by-day with practice it becomes easier. Quitting unnecessary seminal discharge is similar to quitting drugs. It may seem impossible at first, but it can be achieved with determination, and eventually it becomes completely natural.
Train yourself so that the moment a sexual thought arises, remember Krishna's lotus feet, and remember Krishna's lessons in Bhagavad-gita.