Balls. Nuts. Sack. While there are plenty of nicknames for our hormone-and sperm-producing sex organs, how many guys actually know anything about testicle health? For instance, did you know that testicular cancer is the most common cancer in men younger than age 35? Or that about half of all testicular cancer cases are in men between the ages of 20 and 34? That ought to make your jockstrap flinch.

The good news is that testicular cancer, while rare, is entirely treatable if caught early. That’s where regular testicular self-exams come in. Because most testicular cancer growths are painless, self-exams are critical to catching potential problems early on.

How to check yourself for testicular cancer

Step 1: Know thy nuts

One size fits all does not apply to testicles, which can range from grape-sized to small egg-sized, and one is usually slightly larger than the other. At the back of each testicle is a coiled tube called the epididymis, which stores sperm. The rest of the plumbing is called the Vas deferens, which connects sperm to the rest of the unit.

Step 2: Pre-game warm up

If you’ve just taken a plunge in a cold lake, it’s not the ideal time to do a testicular exam. Instead, aim for after a shower or bath when your scrotum is relaxed.

Step 3: Hands on the ball(s)

Stand in front of a mirror and check for swelling on the scrotal skin. Feel the testicles and check them for lumps, swelling, shrinking, and other signs of a problem. Roll each testicle gently between your thumb and index/middle fingers from top to bottom, feeling for unusual lumps or texture. It’s not going to feel completely smooth, so don’t panic. But if you feel a pea-sized lump, get it double-checked by a doctor.

At what age can you get testicular cancer?

The Canadian Cancer Society recommends that by the time guys are 15, they should be well acquainted with their ball sacks. That way, you will be able to tell if there is any change to how they look or feel. Testicular cancer is the most common cancer in men 15-29 years of age. However, men of any age can get testicular cancer. So keep checking no matter what your age is.

Risk factors

There are known risk factors for testicular cancer, such as family history, undescended testicles, and a tall adult height. For the full list, check out the Canadian Cancer Society.

Ball Checker app

Need some help remembering to check-in on your balls every month? There’s an app for that! You can download the Ball Checker App for both iOS and Android

By giving your gonads a monthly once-over, you can ensure there are no lumps, bumps, or swelling to worry about.

Have you tried the Ball Checker App or have other ways to remember to do a self check every month? Tell us about it in the comments below.

This article was originally published on May 27, 2018.