Blue balls, how and why?

As a male I’ve suffered from this phenomena more than a couple of times.

This extreme pain eminating from both of your holiest of holies is crippling! But it seems to happen when hormones are going crazy the actual cause remains a mistery to me.

Can anyone explain how this works and why it happens?

Cecil has spoken on the subject.

Good lord, that article made me wince and cover up several times.