An uncircumcised penis is one in which the foreskin is still intact rather than having been surgically removed. The foreskin is a retractable layer of skin that covers and protects the penis when not erect. When the penis is erect the skin moves down the shaft to reveal the head of the penis. Circumcision rates vary widely across the globe, but according to the U.S. Centers for Disease Control, 79 percent of American men are circumcised.