The Dreaming is the ancestral home of the Fae. It is a realm near our own, separate from our reality but touching it in many places. Some say the Dreaming came from, and is influenced by, the dreams of Man. Others have it the other way 'round. But that discussion is largely academic - what matters is that the Dreaming is.
It is a strange and wonderous place, where anything you can imagine exists. Unicorns, dragons, flying castles made of clouds - these are some of the more mundane things which exist within the Dreaming. Senses are heightened here, or perhaps things are somehow more real. The air is cleaner, the stars brighter, colours are more vivid. Emotions, too, are more intense. A good joke in the Dreaming can make you laugh until your sides ache, and the fear you feel as that dragon roars is enough to make your heart stop beating.