How to stop my boy from touching his private part now and then in the public... is not related to the urgency to go toilet... anybody can help?

How old is your toddler? Secondly could it be something else other then urgency to pee? Could it be that it is itchy? Explain to him nicely that it's not nice to see you holding ur bird bird. Look at other people, do they hold their bird bird? No, so try not to touch ok? If he continue to touch, ask him what is happening, need to pee? Itchy? Painful?