Lol, you're supposed to use talc powder(Medicated Body Powder), baby powder, cornstarch, baking soda, etc. Look up a list for replacements of talc powder if you don't have it.When you have your powder, you rub it on your pubic area, then they don't itch.
I don't know about cornstarch, that'd be odd. Talc and baby powder, yes.