I was reading The Rational Male and something about showing your sexuality made me think of how many sexual cues I try to hide away, and the biggest one - the erection. I think most men learn that erection is a bad thing (unless in a very specific context) and pay a high price to suppress it. It is a personal theory but I believe this suppression has deep roots into the male fear of being sexual with women. This requirement might be the main tool used to create betas/AFCs/nice guys.

Because in order to prevent it, you need to not allow your body and mind become sexual enough, you need to stop it before it gains momentum and do so with extreme prejudice. You see a hot girl, want to approach her, but maybe even before the hamstring the deeper psychological fear is "what if she will see I have an erection?"

Next time someone tells you about how sexually oppressed women are (which they might be) compared to man, tell them what it takes to all your life you need to make sure not to have an erection around other people.