The purpose of penis enlargement is NOT to stretch the skin. By stretching the skin of the penis you are not helping the penis grow. The elastic nature of the skin on the penis makes it expandable without outside help. This means that if you don't stretch the skin, it will work as well as if you do. You will NEVER gain size by stretching the skin alone. You need to move the blood around inside the penis, that is the only thing that will promote growth in penis enlargement.
The first point of the natural penis enlargement program is the movement of the blood through the penis to help promote growth. By pulling the skin of the penis, you are not accomplishing the main goal of natural penis enlargement; expand and optimizing the existing spongy tissue in the penis by moving a constant stream of blood through it.
What this means is that when you are doing the exercises, and milking or bending the penis, you should be concentrating only on moving the blood. The point of the exercises is not to stretch the skin. If you are stretching the skin or if you are worried about your foreskin (on uncircumcised men) then you are not using the exercises effectively. Concentrate only on the blood flow.
Some Suggestions:
1) One of the best ways to get the most out of your program is to make sure that you are applying pressure with the hand that is moving along the penis. This means that if you are making a ring with your thumb and forefinger, you should also apply pressure so that you can feel the blood being pushed around inside the shaft. Lubrication is essential for this to work right, and you should use it on all the exercises.
2) Lubrication is, as stated above, very important. Not only will it prevent dryness of the skin, but it will prevent the friction that can sometimes cause soreness in the shaft, and it will help you optimize your program. Using Vitamin E oil has been a good way to maintain both softness of the skin of the penis and proper lubrication for exercises. Note: if you do the exercises in the shower soap or shower gel work as well.