here is a good video
http://www.youtube.com/watch?v=RdHxMQJ1zCY

Get fidgets and/or a stress ball. Redirect him to that as needed.

Even pinching himself can be a problem - some kids can hurt themselves and not even realize it.

Pinches himself or pinches others? If he is just pinching himself, I would leave it alone.

If he is pinching others because he likes the feel, I would give him something to pinch.

If he is pinching out of frustration, I would teach alternate ways to express frustration. If he's non-vocal, I would try teaching him signs for "No" and "Stop" and "Mine!"

You can make your own fidget with a balloon and sand. It feel close to pinching skin. I would offer the fidget each times he tries to pinch; redirecting every time.

If he mouths things or tends to bite objects, I would go with a different fidget option. There are lots of choices: http://www.therapyshoppe.com/category/8?category_template=374

i believe it is sensory because he could be just happy and then it happens

Why is he doing it? Is he expressing displeasure/anger or does he like the feel of pinching between his fingers? If it's sensory, I would think a fidget toy would work. If it's expressing anger, then I don't have ideas.

how do you stop it? my non vocal 3 yesr old does this. do toys work thanks