The dream command lets you do things while you are asleep and attempt to control your dreams.
dream dream walk dream awaken dream resume
Without a parameter your characters has a random dream.
Dream walk will attempt to move you into the world of dreams.
Dream awaken will attempt to return from the world of dreams.
Dream resume will attempt to return to the world of dreams at the point where you last awakened from it. You may only try this once after each awakening.
Many dream commands require the dreaming skill.