What are the risks of using a cock ring?

As long as you know what you're doing, nothing too frightening. Let's review how to use them securely and what to look out for.

Possible Risks 

Too Tight = Bad Time. If a cock ring is too small or you leave it on too long, you might end up with pain, bruising, or even swelling. Not exactly the fun night you had in mind. Always go for a comfortable fit, and don’t overdo it.
Numbness Is a Red Flag. If your junk starts feeling numb, that’s your body’s way of saying, Hey, maybe let’s not cut off circulation down here? Take the ring off immediately if you notice any loss of feeling.
Circulation Issues. Cock rings work by restricting blood flow, but there’s a fine line between “enhancing” and “uh-oh, my penis is turning purple.” If it starts feeling cold or looking weird, it’s too tight. Loosen up or pick a different size.
Skin Irritation. Some materials don’t agree with everyone’s skin, especially if they’re not cleaned properly. Silicone, metal, leather—each one feels different. Keeping it clean helps prevent irritation or allergic reactions.

More Serious Stuff 

A Never-Ending Erection (Priapism). If your erection sticks around for more than four hours (and not because you're still turned on), that’s a medical emergency. No joke—get help ASAP.
Tissue Damage. Leaving a ring on too long or using one that’s too tight can cause real damage, including nerve issues. If anything starts feeling off, don’t push through—just take it off.

How to Use a Cock Ring Without Regrets

Get the Right Size. It should be snug, not cutting-off-circulation tight. If it’s uncomfortable, you need a bigger size.
Don’t Wear It Forever. 20–30 minutes is the max. Any longer, and you’re asking for trouble.
Listen to Your Body. If something hurts, tingles, or feels wrong—take it off. Sex is supposed to feel good, not like a science experiment gone wrong.
Wash It After Use. Warm water and mild soap do the trick. Keeping it clean helps you avoid infections or irritation.

When to Call a Doctor

Your Erection Won’t Go Away. If it’s been four hours and things aren’t going back to normal, you need medical attention—immediately.
Serious Pain, Swelling, or Numbness. If things feel way off and don’t improve after you remove the ring, don’t ignore it. Get checked out.

Bottom Line
While cock rings may undoubtedly improve your sex life, you shouldn't play around with them irresponsibly. Be mindful of how your body feels, choose the appropriate size, and avoid wearing them for extended periods of time. In this manner, you enjoy every moment without having to deal with "why did I do that?"