DLD I actually read this in the very beginning of my Penis Enlargement "career", I wanted to knew everything
. I don't know where the article is, but if you search "testicles" on wikipedia you will find a paragraph where it says that the sperm production is less efficient at higher temperatures, therefor the testicles are naturally "colder" than the rest of the body. I don't want to fight mother nature (Penis Enlargement is an exception of course
) therefor I personally don't put heat on my nuts.