Questions about heat based contraception

Hi everyone, looking for insite on male birth control. Particularly Heat Based Method and if anyone has used it. Information I've found online in vague. I get it, there is no financial backing by the pharmaceutical companies because there is no money to be made on hot water. There were a few articles and websites, one individual gave very detailed instructions, scientific methods, and personal results.

I'm 36, married, already have 2 children and content to not have more. My wife has no intrest in hormonal birth control, the use of condoms, or surgical sterilization for either of us. Right now we use the rhythm method. So I'm just looking for something help reduce the odds further. If there is a failure and we end up pregnant it's not the end of the world.

Any insite, information, or discussion is welcome. Tweet