The Self-God is the term that my guru used to refer to the ultimate state of spiritual enlightenment. In Rehnadee Shum it is called Emkaeef; and is the highest attainment of enlightenment in it's Path of Enlightenment. It is the meditative experience of union with the Transcendental Divine. In his daily vocabulary Gurudeva, as his disciples addressed him, would use The Self to refer to The Self-God. It is a common refrain from him to ask his disciples every opportunity that he had if they had realised The Self on that day or not. He first used the term The Self-God, and The Self, when he was giving a discourse in his temple in San Francisco in 1959. In that inspiring discourse that urged his followers to seek The Self-God with all their might, Gurudeva claimed that it is the ultimate purpose of human life on Earth. 
All eastern mystical schools that span Hinduism, Buddhism, Taoism and Zen also describe the 'emptyness' experiences of The Self-God as the highest attainment of enlightenment. The experience of The Self-God is actually contradictory to how we understand the word self in normal usage; self refers to one's being as an individual with all the trappings of character, preference and ambition. The experience of The Self however is about the deepest state of quietness possible in the mind that is best described as a non-experience experience. This paradoxical experience is the ultimate state of enlightenment because it shatters all notion of one's self as being ensconced in individuality and personality. The experience confers a deep sense of humility to the Powers-That-Be and appreciation for life and existence that completes the mystics understanding of his or her being and one's place in the grand scheme of Creation. The experience also solidifies the belief of oneness of the Creator with Creation.

Related Links:  Emkaeef; in the Lexicon, The States of Enlightenment–The Kaeefs and Emkaeef; , Youtube video of Gurudeva speaking on finding The Self.