Men, by nature being visual, are likely to create graphic images of women's sexual bodies and imagine watching them, seducing them or, quite often, being seduced by them. For a male, the story line of a fantasy is usually quite genital and accompanied with explicit visual images. Women, in general, fantasize less than their male counterparts. Those women who do fantasize are typically less visual in their sexual fantasies, are usually less focused on genitals, and are more likely to construct a story with the emotional feelings of a romantic encounter. To be sure, however, there are women who masturbate to their fantasies, be they romantic or erotic.
Sexual fantasies can serve many purposes.
They can induce sexual desire, maintain sexual arousal, enhance the sexual experience, trigger an orgasm, and preserve a memory. The desire to be sexual is not something controlled by a switch and easily turned on following the eleven o'clock news. Many people, particularly as they age or as a relationship matures, find that the easy turn ons occur less frequently, particularly late at night. On those occasions when time is limited, fantasies can serve to focus attention on the anticipated erotic event and help induce the desire for sexual intimacy. I need time to psych myself up.