If you don't want to wear clothes, don't. If you want to cover up, do it. There is nothing wrong with the body. That includes the erect penis. I actually think most of them look better hard than soft.
It is not that wearing clothing prevents perverts. Look at catholic priests. A lot of perverts and a lot of clothing.
I think it would be self regulating. In mosquito infested areas, i suspect you would see a lot of clothing. Same in winter. No one wants their tits frozen off.