Although I'm no expert or doctor, from what I have read it sure sounds like the tunica can be stretched. But to get the greatest benefit I do expect a person would need more than weighs. The reason is that the fibers in the tunica run in all different directions. Its a good thing or else a long penis could curve in all different directions.
Since I am on testostrone replacement for hypogonadism, I am expecting I will see some decent growth in the corpus tissue. So I have been incorporating into most my exercises some type of stretch for the tunica. Currently I do 5 different exercises in my routine and I've tried to adapt them a bit for that stretch.
1) I start with rotating stretches and as I do the stretch, I add a bit of twist. With that I notice some tightness about half way in the shaft as well as the normal stretch at the base.
2) Next I do flaccid bends. This really focus on a stretch in the middle of the shaft tunica.
3) Next, Bundled Stretches. I currently am rotating about 180 degrees but when I then pull, I feel in along thr entire shaft , internally and externally.
4) Wet Jelqs. I rotate my hand as I move up the shaft, do a firmer pinch right behind the head and then a slight release as i finish across the head.
5) Uli Squeezes. Really don't do much out of norm except toward the end of my hold i slide up the shaft a bit and slightly rotate trying to create a bit more pressure. I feel the squeezes are already doing an expansion stretch on the tunica that is greater than what I naturally get from my normal erection.
I may be all wet in what I am trying to do, but that is my approach.
