Lucid dreaming is the ability to dream and know that you are dreaming. The experience parallels some of our most enjoyable pleasures. It means that the reality of the dream can be controlled with mere thought. Simply tell yourself you are going to fly. Of course it's not quite that simple.
Some practice is required.
First you must be able to remember your dreams, then you must be able to recognize that you are dreaming, then you must be able to maintain that state once you have recognized it, and then you must be able to wake up one demand so that you can transfer the experience from your subconscious mind to your conscious mind. These four steps are discussed here. During sleep we progress through a series of stages, or levels of consciousness. There are four stages of sleep in which brain waves have distinctive patterns, from an active brain pattern in shallow sleep to a slow rhythmic pattern in deep sleep. Just below the surface you mind is still affected by incoming stimuli such as the light and warmth from the sun, and the movement of the water as the wind forms waves and currents near the surface.