The problem people have later on is that they DON'T improve their technique. That's why they say it's harder to come by. Just like muscles need different stimuli, so does the tissue in the penis. They would go hardcore and fuck themselves up or over do it and they're body reacts the way is supposed to, which is to retract and stay in a safety state.
I believe the tunica actually thins out as you expand. By thinning it out, you force it to stretch to new lengths. It's the healing process that your body does that I believe thickens the tunica. Like how you break a bone, it heals and is thicker at that spot, it won't break at the same location twice. We thin the tunica by stretching it out and letting it heal in an extended state, i.e., wearing a
cock ring after girth or [words=https://shop.mattersofsize.com/products/sizegenetics-penis-extender]extender[/words] after length, [words=http://www.mattersofsize.com/forum/showthread.php?64036-My-Best-Work-Ever-Penis-Enlargement-will-Be-Changed-Forever-gt-gt-Gain%20inches%20with%20SRT-Theory-and-Routine]
SRT[/words] thank you DLD lol. I believe doing it that way lets the tunica heal back to its original thickness but actually longer since it was stretched.
Example, tunica is 1 mm thick and 5 inches long. You stretch it 5.5 inches and thin it to .8 mm. You let it heal in an extended state and it returns to 1mm thick but retains 5.25 to 5.5 inches long given healing ability and tension. Now, the tunica is essentially the same thickness but longer, so it can stretch with the same stimuli to stretch to a new length. So say you used 5 lbs to get that goal, you can use 5 lbs again until the tunica finally thickens itself. Perfect example is a tree, the bigger it gets, the thicker the trunk. Until your tunica gets thicker and needs more stimulus, you can do the same thing until then. So if you start a great routine but stop, I see the tunica thickening up like they say and yes becomes harder to stretch. If they would've stayed in that routine and improved it, the gains would've kept coming. Look how people nowadays are gaining over an inch in a months time and 2 inches in a few months. It used to take years to get 1 inch. They can't sit and say it's newbie gains anymore, we're keeping the tunica in a constant state of unrest and healing. We perfected the techniques and improved our knowledge. Those who say it can't be done belong somewhere other than [words=http://www.mattersofsize.com/join-now.html]MOS[/words] Brotherhood.
This is just how I think it works. There hasn't been true studies done to prove anything. Until PE becomes a household phrase, it won't be touched. They've taken the tunica and other tissues and examined them to test elasticity, but nothing of value as far as PE is concerned. Any length gains showed came from ligament and inner penis being pulled out. The tunica accounts only for around 5-8%. That's almost neglable considering people gain an inch quickly nowadays. Keeping the tunica in constant flux is what I believe increases that percentage considerably. I definitely wanna hear other people's perspectives as well.