Let's make sense for a bit. You do not need crazy supplements to boost your testosterone. Nor do you need to eat herbs or perform natural remedies...
Be a Man.
What you and 99% of other people need who search for natural testosterone boosts need is to hit the gym, have lots of sex, be assertive, eat well, and take care of your life.
I repeat: Sub-optimal testosterone levels, most of the time are not a matter of natural remedies, but a matter of not fully expressing yourself as a man. A man needs to workout, flirt with woman, have intense sex, be respected, take care of himself, be on top of his finances and his situation.
However, there are few exceptions. For example, individuals with varicocele disorder. Varicocele negatively effects the testicles which are responsible for the production of testosterone. These individuals greatly benefit from scrotal cooling and techniques for reducing varicose vein swelling. I have written a complete guide for those with varicocele. Two chapters of the guide are dedicated for scrotal cooling and fertility/hormones. You can get it here.
In any case, whether you have varicocele or not, it's time to take action, stop the excuses and be a man.