Well I’ve got a vag so idk how dicks and balls work other than the few men I’ve dated but since blood rushes there, it can go purple from having blood there for too long just like how a bruise works. That’s the science of it anyway. They probably call it blue balls cause purple probably wasn’t a colour they knew about back then.
If you’re hard for too long? Yes. Apparently it physically hurts and if you’re hard for more than a few hours like you’re on viagra and you can’t calm down, you can have a heart attack or die so it’s pretty serious and they have to literally bleed the dick to restore normal blood flow. It’s kinda scary tbh! Vaginas do something similar but on a far far lesser scale.

Why are the "people" in the comments telling the masses what color their peenar is