I’m not so sure one can say that IR heat is safe.
In order to heat up your testicles similarly, you’d have to spend a half hour in a sauna - and most people can’t stand it that long. Granted, your entire body is heated up which is the reason for the discomfort. But few people go for daily half-hour saunas, which is probably a similar situation (from the testicles point of view) to IR heating daily.
Even if we could say “OK, we killed this batch of sperm, that’s alright, reboot the production”, I am NOT certain that recurrent heating would NOT permanently damage the production apparatus. I think it is prudent to play it safe here.
Simplest thing to do is to hitch up your boxers to cover your balls, textile is apparently good at blocking the IR.
regards, mgus Taped onto the dashboard of a car at a junkyard, I once found the following: "Good judgement comes from experience. Experience comes from bad judgement." The car was crashed.
Primary goal: To have an EQ above average (i.e. streetsmart, compassionate about life and happy) Secondary goal: to make an anagram of my signature denoting how I feel about my gains