Since the dawn of time, men have used the term "blue balls" as a euphemism for general sexual frustration. But if you’ve ever felt some pain down there — or even noticed your testicles turning a darker shade — you know it's not just an excuse to get off.

Blue balls can be something that actually affects you physically, too — and it hurts. But is "blue balls" actually real? And for that matter, is it harmful?

The answers: a) yeah, kinda; and b) nope. Let's investigate.

So is blue balls real or what?

Let's get one thing clear right off the bat: while “blue balls” is a relatively common phenomenon, it's not going to do any long-term damage. If you're having sex and your orgasm is interrupted, you might be uncomfortable for a few minutes (or even hours), but that's pretty much the whole extent of it.

That said, there's not a whole lot science available on blue balls to begin with. We dug up one case report published in the journal Pediatrics back in 2000, which detailed a 14-year-old boy who ended up in the ER with severe scrotal pain after “messing around” with his girlfriend without ejaculating. But the scientists admitted they weren’t quite sure what was responsible for causing the pain.

That’s because, after reviewing the available literature in emergency medicine, urology textbooks, and medical libraries, the scientists were unable to find any mention or reference to “blue balls.” (Might I suggest variations of the phrase, scientists? "Violet testicles"? "Periwinkle package"? Haven't any of these people ever used Google?)

What actually causes blue balls?

When it comes to a dull ache in your balls, the most common hypothesis is that the flow of blood to your penis and scrotum when you’re aroused builds up and, if not released, puts pressure on your testicles that causes this minor pain, explains Darius Paduch, M.D., an associate professor of urology at Weill Cornell Medical College.

There’s also some evidence that a prolonged erection can cause some of the oxygen in your blood to be absorbed by the tissue in your genitals.

This can leave the blood with a blue-ish hue, says urologist Richard K. Lee, M.D., also of Weill Cornell.

But Dr. Lee says this usually only happens when there’s some type of blockage.

“Erectile dysfunction drugs or blood flow-constricting devices like a penis ring could cause this, but it’s not likely to occur naturally,” he adds. So unless you've been using Cialis or a new sex toy in the bedroom, your balls likely won't actually become blue — you might just experience some mild discomfort.

Is there a cure for blue balls?

Yes, and every teenage boy knows exactly what it is: it's called ejaculating, and it's awesome.

Only having an orgasm can relieve this pressure, Paduch says. (Note that he does not say "partnered" orgasm — if you want to finish, and your partner isn't on board for whatever reason, go be a man and find a bathroom stall and a wad of Kleenex and take care of it yourself. Your partner doesn't owe you anything — period.)

Some people have suggested that applying ice or cold water (hello, cold showers!) or working out can help relieve the pressure, but there isn't a ton of research to support that. So for now, just stick to the old-fashioned way.