Fantasies are daydreams. Imaginary visions. Whimsical speculations. Wishful thinking. Everybody fantasises at some level. If you’ve ever imagined what you’d do if you won the lottery, you’ve used fantasy.

Fantasy is a fundamental part of human nature. We see active imagination as healthy in children (watch them playing and you’ll see them lost in a world of their own) but something adults should grow out of. Most people never do, however. Even if we manage to suppress our imagination during the day, all those unconscious passions emerge while we’re sleeping.

Sex generally starts in the brain. So an active imagination can mean you’re ready for sex before anything physical has happened. Therefore, desire is heightened and arousal is much quicker.

Some people find an active fantasy life can add novelty to a long-standing sexual relationship. This can be particularly helpful if your partner is not as sexually adventurous as you are.

But conversely, if you find it embarrassing to experiment in bed, fantasy offers an opportunity to give your imagination free rein and to play out roles. It can be used as a practice arena where you can build confidence before embarking on something new.

In psychosexual therapy, fantasy is often used to block out negative thoughts. If you find during sexual encounters your mind wanders to unhelpful images or thoughts, fantasy can help you to refocus on your sexual pleasure.