Hi Victor,
yes, I have over-simplified --- stretching the tongue certainly is fruitful, but only until the frenum-limit is reached. Once the frenum-limit is reached, milking the tongue does not in itself produce extension. And where exactly the frenum-limit is for you depends on your own individual anatomy.
To explain what I mean by 'frenum limit', I have to add a little more to the analogy.
To make the analogy more complete, the dogs are attached by both soft, stretchable plastic cable and unstretchable rope at the same time. The rope and cable are seperately attached to him and the tree. The stretchable plastic cable is 'muscle'. The rope, which does not stretch, is frenum, which is made of tendon.
Let's say Dog B is attached by a 20-foot rope and a 13-foot plastic cable. He tries to get 15 feet from the tree. He can't now -- he can only get 13 feet from the tree because he is limited by the plastic cable (muscles).
Pulling hard will help him stretch the plastic cable. (This is where 'milking the tongue' produces short-term help). Maybe in a matter of a week or less, the plastic cable is now 15 feet long and he reaches 15 feet. He continues progressing, with the plastic cable stretching until the plastic cable is 20 feet long, as long as the rope. Then he is limited by the rope. No further pulling helps because the rope does not stretch.
He has reached the 'frenum limit'.
Until you reach the frenum limit, milking the tongue can produce quick progress in length. But then the progress stops, and only cutting will get you further.
For me, stretching the tongue muscle gave me about I'm guessing a half-inch max on tongue extension and then I was at the frenum limit. There was no further progress from there no matter how hard and long I pulled. And I still was not far enough for full kechari.
Consider Dog A above. No matter how short or long the plastic rope attached to him is, his 'frenum limit' is at 10 feet, the length of his rope, and no pulling will get him beyond it.
By the way, even though 'milking the tongue' stops producing extension in itself at a certain point, it starts to gain its own value for frenum-cutting because it brings the frenum fibers close to the surface and densely packs them there, ideal for cutting.
Does that all make sense?