What am I doing wrong?

[Pixel556]

I'm guessing excercise is a big factor?

I've thought about it, but I also hear you need to avoid the heating of testicles.

So..It concerns me.

I would say exercise plays a pretty big factor. Exercise and movement assist basically all of your organ's function. I'm sure that this includes the male reproductive organs.

Don't worry about the heating of the testicles. You have a muscle that controls the contraction of the scrotum, so as your body responds to the heat of you exercising it will relax the muscle giving your testes more air/distance from the femoral artery.