When we sit relaxed in our comfortable chair and close our eye after a long day what we try to do is to calm us down from all the thoughts of the day when these thoughts reduces we start feeling sleepy or you can say we are having very few thoughts floating around in our mind this makes our muscles start getting loose , our mind is at the minimum energy consumption mode and this starts our body rejuvenation process , our senses became dull – this state just before we enter sleep is the closest to our SELF state. If we maintain this state in awareness and stay in it for long you will reach a door way to self. It happens only through practice.