Sexual desire is cognitive—involving thoughts, wishes, fantasies, or desires—as well as physical—genital arousal.
It is also thought to be psychosexual, meaning that all of our senses get involved.
Sexual desire is not necessarily the same thing as physiological or genital sexual arousal—though it can be a component. There can be an absence of sexual activity without a lack of desire.
On the other hand, a person can engage in sexual behaviors and activities without feeling sexual desire. So many people engage in said activities so that they can feel a part of a clique with whom they hang out; however, the sexual experience leaves them disappointed.
An understanding of sexual desire and the fact that they do not need to give in to these acts just to “feel good” about themselves can help spare people the heartache that comes from premature sexual activity. (Extract from God Sex book)