foreskin

In male human anatomy, the foreskin is a double-layered fold of smooth muscle tissue, blood vessels, neurons, skin, and mucous membrane that covers and protects the glans penis and the urinary meatus when the penis is not erect. It is also described as the prepuce, a technically broader term that also includes the clitoral hood in women, to which the foreskin is embryonically homologous. The highly innervated mucocutaneous zone of the penis occurs near the tip of the foreskin. The foreskin is mobile, fairly stretchable, and acts as a natural lubricant.