Just before you go to sleep your mind is in a kind of borderline condition resembling hypnosis. You get Random Brain Access, rather trippy like, schizophrenic almost. Sublime noises heard, strange thought patterns etc. You cannot usually remember the last 4 minutes before going to sleep so you have to sort of dive in and get up again to remember it. Having had psychedelic experiences facilitates recognition and remembering. Can be used for selfhypnosis to induce lucid dreaming.