The condition known as phimosis occurs when the foreskin, which is the retractable portion of the skin that covers the glans penis, is constrained or closed, leaving just a little opening for the urine to exit. As a result, while the penis is relaxed and erect, the foreskin cannot be fully drawn back to reveal the glans. The foreskin is often elastic, allowing for simple skin retraction and movement during a full erection.