It’s a know fact that most men do, but don’t freely admit to it. No doubt because of the stigma attached: it’s an adolescent thing and you’re not grown up if you do, or it’s construed you can’t get a woman. As already mentioned, partners and/or wives may object, so there’s also the guilt aspect. Consequently, despite being a natural thing masturbation gets a bad press. But it’s not just confined to men; women sometimes need to scratch as well, but again they wouldn’t freely admit to it.