Sexual curiosity

I’m not sure if I can post about this on here, because I feel weird talking about it. But a young child of mine is self stimulating, which I know is normal even for a 4yr old and apparently even normal for infants, but how do I handle this?? Will it become an issue as they get older? How should I respond. I usually try to distract them by saying “let’s paint!” Or “let’s do this activity!!” Sometimes I do things without thinking, like telling them to stop and not to do that, which is understandable, but I don’t want them to start thinking what they’re experiencing is bad or that they themselves are bad. It’s completely normal behavior that parents don’t get any guidance on. I’m so scared about my children growing into their teenage years.. Parents really need more guidance on how to handle and what to know about children’s curiosity.