Foreskin
The outside of the foreskin is like normal skin but the inside of the foreskin is a membrane like the inside of an eyelid or  mouth. The foreskin is attached to the penis by the frenulum, but it can move. It is very stretchy. On the penis, the most sensitive areas to fine-touch are located on the foreskin. The foreskin can be pierced (have a hole for jewelry put through it) or slit (cut) for fashion reasons. If the foreskin is not cared for (by washing the inside) daily it produces smegma. Smegma is a mixture of epithelial (skin) cells, skin secretions and fluid, which accumulate under the foreskin of the penis. Smegma has strong bad-smelling odor and a bad taste, caused by lactic acid bacteria. The foreskin must be rolled back and washed to prevent smegma.