Rest, sleep on it and then try to read the sessions later.
I am going to give my understanding on this.
The density of being is referred to the level of consciousness, which is accompanied by the appropriate vehicle for the work that is needed for the correct expression of said consciousness.
The higher the level of consciousness, the less tension in the soul, because the higher level of knowledge allows greater autonomy and less dependence on external factors.
The fifth and sixth densities seem to be non-physical in the sense of an environment different from the one we know, in which the illusion is made up of matter, both for the playing field and for the vehicles in which the soul acts.
However, the non-material world, which we cannot imagine or have a clear idea due to lack of information, is according to Ra (Law of One) just as rich or full of illusions in which the soul continues its path of learning.
In short, density is the level of consciousness and the higher the level of consciousness, the greater the ability to interact with creation, with fewer and fewer restrictions.
The density of the body used by the soul, in terms of greater intensity of concentration of matter, may not be correlated with the level of density of consciousness or may be.
It will be whatever is necessary for his being and his level of development.
Of course, behind everything I have said is a maybe.