"exploring"

My daughter is 19 months and started exploring her body. Recently she picked up grabbing or itching or idk what she does down there, I guess feeling.

I know this is completely normal, I'm not weirded out or worried that she does it at home (for now) but I'm at a loss on what I should do. Should I tell her it's inappropriate and tell her not to until she can understand it's inappropriate in public or should I just wait and hope she passes thru it soon? I really don't want her to think it's ok to do it in the mall or elsewhere in public.