Explaining to a five-year-old why another child may not like to be hugged can be difficult, but he needs to learn respect for other kids' boundaries so they don't start to avoid or shun him. Don't make him feel badly about this. Advise him that he can tell other kids in words that he likes them, as opposed to always hugging or "hanging on" them. In this way, you don't ask him to surrender his natural inclination to be affectionate to kids, you ask him to change how he shows his affection. Again, eliminating these behaviors is not the immediate aim here -- although your term, "hanging on," sounds like it would annoy kids -- but, rather, lessening its frequency. Perhaps a little hug or arm around a child's shoulder when meeting and leaving them might be a place to start.
Q
I have two questions. I have a five-year-old son that always plays with the neighbor's four-year-old girl. Is that okay? Also, he is always hugging and hanging on kids -- boys and girls. Is there anything wrong with that?
A
I can't see any reason to worry about your five-year-old son's regularly playing with a four-year-old girl. Don't worry about the age difference and don't be concerned about her being a girl. The fact that he can play with another child and develop a friendly relationship with her is an example of his healthy social development. There is nothing wrong with your son's display of physical affection to other boys and girls. If his frequently "hanging on" them or hugging them obviously disturbs these boys and girls, then you can discuss with him how a hug every now and then is nice but that kids might be bothered by him doing it so much.