Boys have skin that covers the end of the penis called the foreskin or prepuce.
During circumcision all or part of the foreskin is removed. In some faiths, such as Judaism and Islam, circumcision is done as part of a religious ceremony just after birth. Some people do it simply for hygiene and medical reasons, but for most males, it's certainly not necessary. Take the time and trouble to learn to delay orgasm so that it's just as enjoyable for your partner as it is for you. Male circumcision can be done at any age.