That's some really cool observations waterfall_cabin, you can really put words and describe it in a seemingly precise way.
In terms of the exprience, i don't really think it goes beyond synesthesis and body perception involved in multiple layer of projections which form the required layers for concioucness and make it the most potent artform that could ever exist with slight touch of psycho-magic medicinal value. The greatest doors to this vast land of sensations that is mostly foreign to us moderners. Skin and below.
In our daily mode of conscioucness, we can feel vaguely. Sensations is by nature vague, maleable. Yet in this range of sensations though there is an internal organ that can be felt quite easily and that is the heart. It's very accessible because of it's movement that resonates in the whole body. I don't think it would be too hard to learn to people how to feel their blood flow. Veins are right there under the skin, they are visible fractal pattern on the skin.
If we go back to your different points with this notion:
-contact is heavier. Blood is water, the body is mostly water and is heavy.
-energy transmission.
-a "knot" is an accurate image, as is a "map to human emotions", quite literally. Emotion alters the breath, breath alters the hearts, hearts alters blood flow into the organs. Therefor each part of the body and its rivers will be associated with certain emotions.
-water in general is a weird element. We come from it and so it evokes that unforseen obscurity. AS for "overpowering" or "controlling", who can really control its emotions ? In general rather the opposites happen.
-again water is heavy. Yet it might also be that some veins are heavier or located in heavier parts of the body and that would be the ones you are personifying, interacting with.
-yeah chi, it feels really lose ? Mudra is also making blood flow in different ways, it's normal it has an effect on the mind and how we feel.
In Tai Chi, if you look at the movement of a master, they have extremely fluid movement. They are perfectly relaxed. You can't be relaxed if you block you respiration up, which often happens when people are anxious, and which keep things "up". Things need to go down. That's gravity. When contracting ourselves under the pressure felt whatever be the reasons, it will keep blood from flowing, from going down well. So, ... waterfall really.
Standing, if you raise your arm previously loose, it will change the blood flow in your body. You can see the veins becoming thiner if you're on the thinner side, or just feeling it. Mudra is this: if you for exemple raise the index but let the rest hanging, there will be a similar change of flow that is targeted because of the use of this precise thinger. And then it's possible to organise each position of the body, the infinity of them, in relation to what part of it is at what angle from the ground - with five basic realtion to gravity being: loose, all the way up, in between, and both in betweens that comes from this middle.
If it cannnot be very accurate yet i can't help but see entities in general as personification of blood flow. When meditatin a lot i had those feeling of insects running over my bodies, it took me some times to get it was blood flow and at first i really wasn't sure what it was. So this image that is both reccurent in regard to schizophrenia or hyperspace trip is very interesting because veins looks like trees and insectes runs on the trees following their patterns, or more simply when they run on our bodies laying in the grass, it's the basic pattern it will make. Snakes or dragons are more obvious as veins, visually are like tree branches. So what happens is the same thing as seeing face inside tree branches. If only that this time it's the branche that makes you. In the same sense that a Mudra, is a complex visual pattern you can both see and feel. And then there's all sort of synesthesic thing, blending the images of the bodywith sensations and between them (which could be decribes as mind-yoga and be accurate)(and which someone more scientific than me might enjoy because it makes new neural embranchements too). As far as reptiles go, i'd say it's a very grounded, almost realistic level of it and concerned more with the belly region, which is correlated with the mouth region which is all paddy puddles and rivers end. For jesters, we'de be more on the surface, close to the air and all of that. Different flows.
A definiying characteristic of mankind is that we cry. Water goes up there. The sensation is not that far off blood flow too, when a tear rolls down your cheek. If only a little less cristaline.
Anyway, i'd say give tai chi related martial arts a go if you want to learn more about it through experience.
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