Flapping happens due to the child's need for stimming. As the child grows, the nervous system matures and he'll feel less and less the need for it. Plus we all

Flapping happens due to the child's need for stimming. As the child grows, the nervous system matures and he'll feel less and less the need for it. Plus we all do it in one form or another, even if what we do is more socially acceptable - like nail bitting or gum chewing.