It is interesting to consider how the relationship between sleeping states - deep sleep and dreaming sleep - and the awake state may have changed through the evolutionary development of Men.
If we start with the historical (and early childhood) conscious state termed Original Participation by Owen Barfield; then it was a striking idea of Rudolf Steiner that this is characterized by what we would consider a less complete difference between sleep and waking. The awake person was not so fully awake is the case now; and aspects of deep and dreaming sleep remained active throughout the daytime.
This would be a more passive and unconscious form of waking; whereby we were involuntarily influenced by the sleeping states; immersed-in them. In Original Participation Man's consciousness was integrated, but dominated by sleep.
A suggestion is that the sleep states are (in some fashion) in communication with the divine and spiritual world; and therefore in Original Participation awake Man has direct experiential knowledge of the gods and spiritual reality. This may be why all early Men and all young children assume the reality of gods and the spiritual realm - because the experience and know it; not just when asleep but all of the time.
The idea is that, as Man's consciousness evolved through history, the division between sleeping and waking states became more distinct; until with modern Man it was complete (the phase called the Consciousness Soul). We are not aware of our sleeping and dreaming consciousness while awake (although they continue); and indeed we almost never remember anything from deep sleep, and even dream memories tend to be absent, partial or uncertain.
It struck me that presumably the same applies in the opposite direction: that waking consciousness has probably lost access to deep and dreaming sleep. Perhaps in earlier phases, waking consciousness could affect dreaming sleep, and even deep sleep; and therefore in original Participation these sleeping states were more conscious, more subject to waking motivations, and probably more memorable.
Whereas nowadays (for many people) dreams are characterized by their own crazy illogic and irrelevance; perhaps for early Men they were coherent, useful, memorable - by the waking Man. And maybe something analogous applied even with the slower, simpler, 'tidal' consciousness-world of deep sleep.
(Steiner suggests that in dreaming sleep, ancient Man - and children - are in communion with the lower angelic powers; and in deep sleep, the higher angels - or, I would guess, perhaps even the simple and basic aspects of the knowledge of God, Jesus Christ and/or the Holy Ghost.)
So, modern Man's consciousness states are not integrated; but instead divided, alienated, encapsulated.
And what of the goal of Final Participation? We might assume that the division between sleeping and waking would again become crossable, 'permeable' - but this time dominated by waking consciousness and by its capacity for free agency, for conscious choice.
Thus we may be able to choose to bring our waking consciousness and cross into dreaming, and even deep sleep; there to both gain conscious control of these states, and to remember better what happens in them.
So we may again become integrated in our consciousness; but this time with awakeness dominating.
However, this state is voluntary - not automatic; conscious not unconscious; and is subject to the constraints of Final Participation - which is, after all, an attainment of divine consciousness (albeit usually partial and always temporary) even when we are mortal on earth.
Therefore, we might be able to choose to bring awake consciousness into dreaming and deep sleep; but only insofar as we our-selves are aligned with God's purposes, meanings and mode of thinking.
If a person has chosen the side of Satan against God, then Final Participation is not (at that time) possible.
Furthermore sin interferes with Final Participation. Un-repented sin blocks FP in the long term (because we are not aligned with the divine); while currently-active sin in thinking will curtail FP for its duration; which is surely one reason, albeit not the only reason, why Final Participation is always temporary - indeed usually very brief.
Nonetheless, even with all these provisos, this gives an idea of what to aim for in Final Participation how to go about it; and how to know when it has happened. That is, we can aim towards more frequent and fuller integration of the waking and sleep states; do so consciously; and within a Christian context.