"Blue balls" is just a term, they don't actually turn blue. But yes, when you get a man "hot and bothered" so to speak, and there is no release, the testes can become painful (which may last hours or days.) I've personally experienced this, but I've also used it as an excuse to go farther (boys are tricky like that.) Not sure if that's helpful other than the fact that yes, blue balls do exist but arent blue :)
