Continuing on another aspect of this....In my astral projection experiences, my sense of touch was pretty much completely dissociated from my physical body. This sort of goes along with what I said about mental models. Gab, in your experience while awake, it sounds like you could still feel your physical body simultaneously. This seems to support the idea that the experience of the 'astral' body is more than a mistaken tactile hallucination of where your physical body is.
I didn't notice any vibration at all, but I wasn't paying attention to that either. Certainly there was no buzzing or large vibrations like some people experience. I've guessed that kind of vibration is due to sense of touch and/or hearing oscillating between two different states, rather than it being from feeling or hearing something that is vibrating. (In other words, its the sense that's vibrating in that case, not what is being sensed.) It sounds like the vibration that Gab experienced is different than that though.
It seems to me that a person ought to be able to feel that kind of vibration all the time, once a person knows what to pay attention to.
Gab, can you tell if the vibrations seem to become higher in frequency before you feel your astral body, or higher in amplitude? This is like the difference between higher pitch and higher volume. Both cases are higher energy. Don't go from what other people say, they don't have these kinds of distinctions straight.
If I think about feeling in my whole body at once , I can cause a sort of avalanche of feeling, like what some people call a full-body orgasm. This is particularly easy to do if I pay special attention to the top of my head and my spine. Experientially this would be an amplitude kind of thing, not frequency, but nerve impulses use higher frequency to represent stronger impressions. I'm guessing that the 'vibrations' you experience have either to do with nerve impulses or with how the information is represented in your mind, rather than a vibration of some thing that you're sensing. I don't think you can experience vibrations of particle physics, like in string theory, as vibrations of your astral body. I don't even think that would work for something like oscillations of electrons. The scale is completely different. Feeling that as a vibration would be like trying to build a working microscope out of bricks. I think the 'astral vibration' has to be some more macroscopic behavior of the astral body, like waves moving through it. In other words, the body is vibrating. If the matter itself is different from ordinary matter because of something having to do with vibrations, I don't think that it makes sense that those kinds of vibrations would be felt that way.
To understand any of this stuff, I think a starting point is to recognize that one's experience of one's physical body is a mental representation of one's physical body, that its not a direct experience of one's physical body. I think that if a person doesn't recognize that, or doesn't see any of the implications, then most conclusions they draw about astral reality are unavoidably wrong. As I've posted previously, the reason I care about this is I think that our whole astral paradigm with vibrations and whatnot is mostly wrong, and if someone could come up with a more realistic way of thinking about it, we would all have better experiences. Since this sort of thing is psychically shared, people who aren't interested in intellectual discussions wouldn't even have to think about it, but they'd still be able to imagine a better representation of the experience, in other words a better experience, based on what they feel about how other people think about it. Even the stuff about vibrations and finer bodies is a collection of thoughts that other people put thought into developing, and if they hadn't made that effort then we wouldn't even have that.
To try to better explain what I mean here by way of analogy....We are able to see using our eyes because natural selection trained the structure of the brain and the eye. It doesn't just happen by itself, if our eyes were not lenses for instance it wouldn't work at all. Then on top of that our brains had to teach themselves to make the right connections in infancy. Without that training you would be completely blind, even if your eye and brain started out fine. (This has been verified through sick sensory deprivation experiments with baby animals.) As a minor example of this, one of the last things to be learned is how to judge size and distance. I have a very vivid memory of seeing a bumble bee that was as big as a small rabbit - it really appeared to me that way. And I've seen other small children make similar mistakes, such as thinking they might fall into a small crack in the ground. With the astral stuff, even if our bodies are already designed by providence to be able to do this stuff, we still have to learn how. Its as if we're trying to see and we don't even have the shape of an eye, we have to imagine it into being. As a similar example, I think that a person who thinks in terms of signals being sent between people is probably at a big disadvantage in learning to share dreams, because that's not how it works. And someone who thinks in terms of 'me' and 'not me' can't do it as easily either. A lot of the steps we take are by providence, like an older person holding our hand, but we have to do the work of developing that kind of thinking ourselves or it won't stick. That's how it seems to me anyway.