I'm gratified to see that some intelligent people are willing to speak up and shed light on the sexually suppressive nature of all male dominated societies and cultures where the ethos is geared toward war, punishment, and aggression. And just exactly where has this now archaic form of male dominated barbarism gotten us? It has bought humans to the very edge of self-annihilation and extinction. Its time to open the mind and let some light in regarding the fact that sex is the affirmation of life and its too often violent suppression the social and cultural equivalent of what Sigmund Freud called the Death Wish.
Common sense would seem to indicate that there is indeed a time and place for everything and that some people are not always very mindful of this fact; however, when it comes to the issue of human sexuality, ignorance of the facts, social backwardness, and outright stupidity can be found anywhere and everywhere and always is!
Males are raised to hate their bodies not by women but by the institutional framework of a patriarchal social order that exalts war and individual acts of aggression over all else including the life instinct that Freud called libido.
Our Native American ancestors often called the white man "the brilliant moron" and for a very good reason! He had the ability to create vast material abundance but lacked the ability to enjoy even the most basic and natural pleasures that Great Spirit and Earth Mother have provided us with as a means and method of being one with the Devine.
Erections happen from time to time, in locker rooms and elsewhere. There is no need for shame if one arises, just common sense to make sure no one is offended. In locker rooms, towels are helpful, on the beach, turning over is often the best option, and so on. No big deal.
(I'm always amazed at people who think nudity is natural, but erections are unnatural and shameful. To me, erections are natural as well. But as usual, other people's feelings must be taken into account.)