Greetings Audi,
Your ramblings are great...
You said concerning the meaning of the expression "Fang song" :
<...In my opinion, the Yangs usually refer to something more specific than either of these two meanings basically they want you to continuously extend your limbs, as though you were trying to physically unlock and open your joints. In my opinion, this process takes more energy, rather than less and can be physically demonstrated. When the Yangs do this, they do so from what is basically a static posture. It is not a concept that applies only to movement and is not directly concerned with the level of muscular exertion. The focus is on the joints, tendons and sinews, not muscles, positively or negatively. To get the right feel in your joints, tendons, and sinews, you must use your muscles in a certain way. > Audi
<...This is also one of the reasons why extending the fingers ("shu zhi") is important to the Yang's system. This extension is part of te same feeling of "song" that threads throughout your body. If you merely "relax" your fingers and allow them to go somewhat limp, this will run counter to the feelings the Yang's want you to cultivate. > Audi
So, from what I understand from your posting, "Fang song" is more like STRETCHING than SLOUCHING.
A recent demonstration assisted me in understanding this concept you explained.
I find that the concept of "lowering oneself throughout the form" as I have heard said, raising the back, sinking the chest, and "loosening" or "sitting" at the waist, perhaps lends to the false "impression" of a slouched, traditional, literal type of relaxation...To the untrained observer or student...Whereas other aspects seem to really be more visibly stretching, such as the straightness in the spine and the "head suspended" from above.
Another hint at "The straight within the curved" ?
You also mentioned:
<...If one fixates too much on "waist rotations" one can convert this subtle zigzag feel into an incorrect feeling of "spin right" and "spin left" and lose the feeling of the straightness of the advance and the feel of the opening of the hip sockets to initiate the steps> Audi
Yes, I am beginning to notice coarse and subtle differences between the straight and the curved. I think it is something I must now address and cultivate posture by posture, one by one.
Also,
<...In this posture, the left hand and arm sweep first to the right and then to the left, as in "Brush knee and twist step, Left("Zuo lo xi ao bu"). These sweeps can give the feel of the "merry-go-round"plane of rotation. It is easy to transfer this feeling to the right arm, especially the initially rightward sweep of the left arm, but I believe such a tranfer to be incorrect. The right forearm should instead move in something of a "ferris wheel" plane, with the right elbow drawing back directly to the east, rather than rotating clockwise in a horizontal plane to "match" the rightward movement of the left arm. Basically the right elbow does not rotate in the "merry-go-round" plane at all in this posture.> Audi
I think this also incorporates the "cross- substantial" movement, or that's what I notice...The idea that the right and left upper limbs necessarily move quite independantly(Yin and Yang) ; with separate intent, disposition, purpose, speed etc. in unison with it's opposite sided lower limb, although this is not always apparent or visible(especially to the unrtained eye) .
You also spoke of:
<It is also easy to mistakenly ram the right arm straight backward as if cocking a gun or chambering the arm, as is done in Karate. Instead the movement of the right fist initially describes some of a ferris wheel circle. It pulls back to the level of the hip socket, not to the level of the ribs, before "reeling" of in a straight line for the punch. > Aodi
Good point,
This reminds me of the "training with circles" discussion, with one ball sitting "consciously" within the crook of the drawn back right arm, one cannot close at the elbow. I find that 'circle system' to be a great way to maintain open spaces and circularity in the overall effect.
<The Yi leads, and the Qi and Jin follow>Audi
Very nice, but I am at a complete loss as to what jin means exactly and what the distinctions between Qi and jin would be.
You also stated:
<All this is, of course, quite easy to say, but not so easy to do. First you do it in one movement of the posture, then you do it in two, then three etc. After a while you begin to see many of the patterns of repetition in the form, and most of the movements begin to feel like minor variations of each other, or rather, different combinations of the same variations. > Audi
Hmmm...I'm not quite there yet...but the form does seem to grow shorter and shorter each time I do it. "Over already"...it used to go on and on and on. It's interesting to go through all these changes in perception, probably useful too

.
Thanks for all the explanations you have provided!
Best regards,
Psalchemist.