The foreskin - What it does
The foreskin - What it is
The foreskin is special in that it is not directly attached as most skin is. It is free to slide up and down the shaft of the penis with almost no friction. The foreskin can be thought of as a continuation of the tube of skin that covers the shaft of the penis, but much longer. This tube of skin is firmly attached only at the base of the penis and at the head of the penis. In between the points of attachment this tube of skin has the special property that easily slides on the shaft of the penis rather than being firmly connected as most skin is. The foreskin's length and the fact that it is unattached in the middle allows it to slide up and down the shaft of the penis and roll in on itself over the head of the penis (see diagram below).
The foreskin is long enough so that it continues down the shaft of the penis and rolls in on itself over the head of the penis. For those of you who are only familiar with circumcised penises, that means that an intact penis has two to three times as much skin that a circumcised penis.
A foreskin is long. An intact penis has two to three times the length of skin that a circumcised penis has. When flaccid, most of this length is taken up in the double fold of skin covering the head of the penis. When erect the foreskin can roll back to allow the penis to lengthen while still allowing the skin on the shaft of the penis to remain loose. The foreskin is often long enough to cover the head of the penis while erect.
The foreskin is extremely sensitive. It is filled with nerve endings called stretch receptors that fire when they are stretched, rolled, or massaged.
An intact penis, erect with the foreskin being retracted
Things that are not obvious from these pictures:
The head of the penis has no skin. This may be a surprise to those of you who are familiar only with circumcised penises. The head of the penis is actually covered by a very thin moist mucus membrane, very much like the inside of the lip or the inside of the eyelid. The head of the penis is not meant to be exposed to the elements such as friction against clothing, friction during sex, the sun's rays, or soap (in infants urine or feces). The head of the penis is supposed to be protected by the warm, moist coccoon that the foreskin creates. If the foreskin is remvoed, the mucus membrane of the penis thickens in response to the lack of protection. It may look like skin, but it is not.
The foreskin is lined with smoothe muscle fibers which contract to make the foreskin wrap snugly around the head of the penis. These muscle fibers can relax to permit the foreskin to be retracted.
Friction. There is no friction.
An intact penis, erect with the foreskin being retracted, another
The frenulum is a Y shaped web of skin that connects the foreskin
to the underside of the head of the penis. The frenulum is kind of
like the web of skin under the tongue. This is the most sensitive part
of the penis, containing a huge number of nerve endings. Circumcision
usually removes all or most of the frenulum. For more information see
The Effects of Circumcision by Glenn M.J. Epps' Circumcision Facts.