The penis primarily consists of what could be called a stem and an acorn. The "acorn" tip is very sensitive and protected by a thin fold of skin. In some boys this covering is complete, while in other boys the covering is only partial.
In most cases the foreskin is adhered to the acorn. This adhesion usually resolves itself. Around age 6, 90% of foreskins have freed themselves from the tip of the penis. Generally, by aged 10, the foreskin is completely free of the tip of the penis.
Generally there is no reason to be concerned if the foreskin is entirely adhered. If you are anxious, it may be worth visiting your family GP.
Foreskin cleaning and care
Underneath the foreskin, an oily film forms, this film is called smegma. The skin of the penis should be washed regularly, otherwise infection and inflammation can set in. Cleaning the smegma can only be accomplished when the foreskin has come free. You can try this once the boy is around 3 years of age, try this somewhere like the bath. The accumulated smegma can easily be washed away, and when done regularly your child will learn this is a normal ritual, like bathing or brushing teeth.
From angelababy In Q&A