Increasing intensity is based on the time period and when your penile sensitivity adopts to the stress load. Here's an example:
When you're doing a manual pull straight down, and then up, for the last 2 to 3 weeks, roughly around 2.5lbs to 3lbs of pulling tension, your penis feels relaxed without any pain. This is where you will need to increase the intensity up. First, you need to pull until you get that dull feeling, as if you're getting a strong pull but without any pain. The pull feels like something is stressing but that dull sensation of the pull is no where painful. If you can meausure that pulling stress load, or known as traction load, record it as a your moderate level. It can be somewhere 5 to 6 lbs.
Now, from there, go up just a little bit more. That dull pull that feels like something is being uprooted then turns to a dull but slightly tingly feeling without the pain. When you hit any kind of pain, you're going too far. Back off just slightly to get that tingly but dull pulling sensation. That is your upper traction load. It may be 7 to 8 lbs. Measure if you can so you can get to know your range at all time.
Start from the lower limit where you are now to get the warm up stretches because your penile tissues adopts the current comfortable traction load.
Then, from 2.5lbs to 3lbs (as an example), you go up to the moderate traction load just for a few minutes for the exercises to loosen up the tissues a bit more.
Then switch from moderate to upper traction load for a few more exercises to optimize your maximum lengthening capacity.
Lastly, switch down between the lower and moderate traction loads and stay in this zone for the rest of your exercises. Once you reach the high traction load, your tissue are primed and will continue to stretch. You don't need to remain at the high traciton load zone to keep things stretched. Stay and the low and moderate traction loads to prevent your tissues from sudden shocks, triggering the preservation mode. This is when your penis retracts and turtles to protect itself.
