This is a very common question. Usually the foreskin should slide back on its own when you get an erection. It may be a little loose or not come back completely, but this isn’t a problem. If your foreskin doesn’t come back on its own, I would mention it to your doctor – sometimes, the foreskin can be too tight and make it uncomfortable when you have an erection. Sometimes a tight foreskin can also make it hard to pee or clean your penis properly. These problems can be fixed by a “urologist,” a doctor who specializes in caring for the male genitourinary system.