hypnagogic \hip-nuh-GOJ-ik; -GOH-jik\, adjective:
Of, pertaining to, or occurring in the state of drowsiness preceding sleep.
It is of course precisely in such episodes of mental traveling that writers are known to do good work, sometimes even their best, solving formal problems, getting advice from Beyond, having hypnagogic adventures that with luck can be recovered later on.
- -- Thomas Pynchon, "Nearer, My Couch, to Thee", New York Times, June 6, 1993
. . .the phenomenon of hypnagogic hallucinations, or what Mr. Alvarez describes as "the flickering images and voices that well up just before sleep takes over."
- -- Christopher Lehmann-Haupt, "The Faces of Night, Many of Them Scary", New York Times, January 9, 1995
His uncensored and uncensoring subconscious allows him to absorb the world around him and in him, and to spit it out almost undigested, as if he were walking around in a constant hypnagogic state.
- -- Susan Bolotin, "Don't Turn Your Back on This Book", New York Times, June 9, 1985
Hypnagogic (sometimes spelled hypnogogic) ultimately derives from Greek hupnos, "sleep" + agogos, "leading," from agein, "to lead."
Works for me to the extent that I was lying awake at night way past my bed time just to get to the end of the episode.