The Out-Of-Body experience is much misunderstood. It is desired by many but experienced by few. The entity, driven by curiosity or strong emotion, flits out of the physical body, desiring more mobility. Once the spirit learns how to jump out of the body, the human finds they can go out of the body at will, but they cannot describe the mechanism as it is, after all, a skill of the soul, not of the human body that the soul inhabits. Out-Of-Body is not a particular position or a particular mind set, and it is not really a voluntary activity on the part of the human. This is not something that a human can teach itself, because it is a lesson that the soul must experience.
Most often, in humans, it occurs in trauma or impending death, the sense of the spirit that the body will die. It is stepping away as though jumping out of the fire. The soul often jumps out of the body just as death is happening, as those who have come back from Near Death experiences can relay. They were watching the scene. Even though the point of death experience is remembered by spiritus, this pales in the flood of other experiences and tends to be not remembered until a similar instance returns, such as the death of the current incarnation.
Once entities learn how to do this, they want to do this often. If they don't return voluntarily, on their own, they are returned by their spirit guides, who watch over the incarnated entities like school yard monitors, ensuring that the incarnation proceeds by the rules. These temporary exits are self limiting, as the guides force the entity back into its physical body after a time. No skipping out of school. During 3rd Density the entity is required absolutely to be incarnated, as this is where it learns the fastest. There are occasional Out-Of-Body experiences, but in the main, 3rd Density is a grounded experience.
During 4th Density the entity is also incarnated, but is aware of the potential separation of the spirit from the body, and Out-Of-Body experiences are openly discussed among all - a fact of life. 4th Density is a long plateau, where many lessons are solidly mastered. During 4th Density, the entity increasingly finds itself Out-Of-Body, and thus is getting familiar with life without a body. Moving into 5th and 6th Density, then, the entity is comfortable without a body, and finds its learning experiences can continue apace with or without. However, depending on the determination of the entity and lessons to be learned, these 5th and 6th Density entities may find themselves incarnated, even back on a 3rd Density world such as the Earth is at present.