There is nothing wrong with turtling; here again, we have a visual that seems counter-productive to gains since who wants to look at a thimble sized dick. Trauma and cold are the two most severe turtling forces and that is perfectly fine, to turtle is to heal, its nature’s way of protecting the penis. The penis will seek the warmth of the body and seek to find healing agents, so its a good thing. I believe it is incorrect to say, “we heal in an elongated state,” the changes happening to the penis to make it bloom larger are internal. The erection grows larger as a consequence of improvement to the erectile circuitry, hence the blood and tissue resistant to expansion must be improved. By improving blood pathways (enlarging) and breaking down ligaments (weakening) the erection can grow larger under the same erectile pump. So, it is analogous to any flowmetric system; if you have a pump with a horsepower rating of 1HP, and you do not have the budget for a new pump, if you increase the diameter of your pipes and you clear any occlusions you will generate a higher flow rate under the same pump.
So, to answer your question, and what I would propose. Its a slow process widening the pipes and breaking down the physiology of resistance, but the exercises that weaken tissue and expand blood carrying tissue are the objectives to a larger penis. This is why you can go very long periods without gains, and then, all of a sudden you look down and you are big (its like you unclogged your pipe), and in fact, that is what you did. When blood has been given a higher flow, and the vessel has been weakened to accept more blood you have a bigger erection. So, the objective is to stretch, hang and weaken and expand. Good luck.