Getting Your Balls In Hot Water Might Be The Next Best Thing

A German designers’ new male contraceptive device gives a new meaning to the term busting your balls. Rebecca Weiss’s device, Coso, is a male contraceptive device that uses ultrasound waves to temporarily halt sperm regeneration.

Rebecca Weiss / Credit: Weiss’ Instagram

How does it work you ask? Well, you kind of have to boil your testicles. No, really. But if you want the scientific description; a person would fill the Coso device with water up to the indicated mark, turn it on so it heats to operating temperature, and sit for a few minutes with their testicles dipped into it. The ultrasound waves then go to work, temporarily halting the sperm regeneration process. It takes effectiveness two weeks after the first application.

Credit: Screen capture

The allure of Weiss’s invention is that it is reversible. The effect isn’t permanent, like a vasectomy. Male fertility is expected to return no later than six months after the last application. I’m sure that Weiss’s ingenuity will have men from all regions of the world, boiling their balls right before they head out on a Saturday night.

Like many inventions, Coso too was born out of necessity. Weiss herself had an issue – and she looked for a solution. She was diagnosed with a cervical cancer precursor that meant she could no longer take birth control in the pill form. So she along with her partner looked for alternative methods to have responsible adult fun but found out there were no male-centered options beyond the condom or the (dreaded) permanent vasectomy. And that’s when the wheels started turning. Weiss began exploring the topic more as part of her master’s thesis in industrial design at the Technical University in Munich.

“The problem is not unique to me personally…

It affects many others as well. This is also evident in the current growing public discussion about the lack of contraceptive alternatives.”


Weiss’s hope is to make Coso as user friendly as possible. She feels that new technologies only work if they are accepted by society.

“Coso, in contrast, offers a user-friendly contraceptive approach that is easy to use without any kind of physical intervention, pain or previously known side effects…

New technologies only work if they are accepted by users and society.”

In an effort to make Coso very user friendly, Weiss surveyed more than 400 participants for the device and included 25 of them in design workshops. She consulted with experts from urology, andrology, sexual therapy and psychotherapy. She then began making and testing cardboard prototypes. The design that Weiss ultimately ended up with – has won her The James Dyson Award, a prestigious award that recognizes excellence in student design and engineering on an international level.

Credit: Screen capture

Coso is still in its development stages and is seeking financial support for clinical trials, so that they can collect accurate and proper data. Without valid data, Coso will remain to be just a concept and not a readily available product for consumers.

Do you think Weiss’s Coso invention is a refreshing take on traditional male contraceptives?

4 thoughts on “Getting Your Balls In Hot Water Might Be The Next Best Thing”

    • It is not proven that the ultrasound wave will stop reproduction of sperms so it could be deceptive or deceiving that it will be pregnancy proof or 100% reliable. It might be creating more problems because if it doesn’t work, you may be in birth creation!

      • Right, how would you even test this if it takes up to I believe 2 weeks and lasts up to 6 months… Does this stupid thing come with a free microscope made in China to see if you had enough “Applications” for temporary sterility. The latest form of Russian Roulette.


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