| The physics of the foreskin |
Because circumcision involves the removal of a variable amount of skin, it is important to understand the dynamics which define where the skin stays on the penis for each state of the penis from very flacid to completely erect.
In order to acheive te desired cosmetic result for your circumcision, you will need to understand how much skin will need to be removed or preserved in order to acheive the results, based on the variations in size of your own penis.
The skin of the penis has a natural state, a stretched state and a "compressed" state. In the stretched state, the skin will attempt to shrink to its natural state. In the compressed state, the skin will attempt to expand so it covers a greater area allowing it to be in its normal state.
In a moderate or loosely circumcised penis, during the flaccid state, the skin on the shaft has some level of compression and hence a desire to expand. However, the force to make it expand is smaller than the force required for the skin to stretch to go over the corona. As a result, the skin usually stays "bunched" up against the rim of the glans to a varying extent.
After circumcision, over time, because the shaft skin will not have its diameter stretched regularly, it will require greater force to make it go over the rim of the glans. This also happens to uncircumcised males who keep their foreskins retracted all the time.
Circumcision changes the length of the skin on the penis, and thus changes the skin length force. Studying the effect of the "physics of the foreskin" is very important if you elect a loose or partial circumcision.
Not only is the length of the skin changed, but the foreskin opening force is also greatly modified with most circumcisions. A long foreskin has its tip narrow in its natural unstretched state and has the ability to stretch greatlty. As you retracts the foreskin slowly, the normall small opening is stretched, giving an increasing resistance to being retracted.
After a partial circumcision, you are left with the tip of the skin whose natural diameter is closer to the diameter of the rim of head and hence, for the foreksin to retract behind the rim, the foreskin opening force will be smaller since it need not stretch as much.
In the uncircumcised with long foreskin, partial erection can often be acheived without much of the glans being exposed since the foreskin length force is smaller than the foreskin opening force. Thus there will be a certain amount of tension on the foreskin length, a force balanced by the resistance of the foreksin opening to widen.
However, in a partially circumcised penis, because the foreskin opening force is very small, any change in the foreskin length force will result in the foreskin moving back. Thus, even at the onset of erection, the remaining foreskin will begin to retract. This becomes a significant parameter when deciding how much skin must be removed, especially for male whose penis varies greatly in size between the totally flaccid state and the fully erect one.
Similarly, for loosely circumcised males, if the penis shrinks in length enough for some skin to go over rim of head, that skin will retain the easy diameter stretching ability and thus will continue to be able to cover part of head when very very soft and stay wide. This has cosmetic implications when flaccid, but also for masturbation technique during erection. A skin that has retained its easily stretched diameter is more likely to be able to be pulled over part of the glans and/or the rim during masturbation. A skin which never goes over the rim of glans when soft is more likely to "stop" at the rim and view the rim as too high a "hurdle" to jump because it is not used to have its diameter stretched that much.
It is important that one consider the forces involved when determining how much skin needs to be removed in order to acheive the desired results. The shorter the foreskin is cut, the lesser the foreskin opening force will be and proportionally greater the coronal force will be. At one point, the coronal force will be great enough to pull the remaining foreskin back down from the rim of head. with the skin staying loose/bunched up behind the rim of head unless the penis is very very soft.
This is probably what distinguishes a partial circumcision from a loose circumcision. When the foreskin is planned to cover less than half of the glans, you can expect the remaining foreskin to spend much of its time fully retracted and thus be considered more of a loose circumcision than a partial circumcision. Again, this all depends on how much your penis shrinks during its flaccid state, and if there is a significant difference in size when it is soft in your underwear versus soft when naked.