I made the assumption and leap to protect them from heat. Sperm production is best at a bit below body temperature. Hence why testicles evolved to hang from the body instead of being contained within the abdominal cavity. 

 I was today years old when I learned why ears hang low 

 
https://image.nostr.build/2eb8f79902fbfd67a873c06de07a1b63f21b581fa917ce41443827eed164c4ce.jpg#m=image%2Fjpeg&dim=1029x698&blurhash=rFI%7DS8%3FHtmRkMdaeX9X9WA9s%25LW%3FM%7CenjGbIofaz%3F%5DWr9FjYR%2Bozaet6of%25gWXxuj%3Ffkoes%3AogRj%25%23t7snWCofoLR%25WUWC%7EWM%7BxukBS2oyRijFj%40&x=5d555aaf6931bbe66f000975aa50aa9cdade5e55f3b69884a5b6c976e267d0d6 

 Hovering your balls above the tub water is the new sun your balls.. didn’t you know? 

 Knowledge is power 

 Indeed 🙌 

 😉🍻