Some herbs can make them bigger over time:
Panax ginseng, maca root (black maca is best for the male gonads) tongkat ali, and probably horny goat weed. Also taking a multiple vitamin along with 50mg of zinc balanced with 2 mg of copper, wearing 100%cotton boxer briefs, gently massaging every day with extra virgin coconut oil or black castor oil, no soy, taking an estrogen suppressor like dim and some aerobic exercise and a protein powder every day should yield an increase in size of your family jewels over time. Also not ejaculating too often will help and taking a good dose of omega threes like in cod liver oil and drinking plenty of purified water for nutrient absorption and increase in semen.
Also celery will help by increasing semen.
Lastly the probiotic lactobacillus reuteri has been scientifically shown to increase ball size in rats. Trace minerals taken internally will nourish them and iodine applied on them may increase the size of them and is also nourishing to them.
The blakoe ring of power is supposed to help and if you can expose your balls to direct sunlight, they will definitely thank you for this with increase in Testosterone.
Try to eat only organic foods with no pesticides and limit exposure to plastics to keep estrogen out your body. Keep cell phones and lap tops away from them. Hope this helps.
I have done combinations of these things and noticed an increase even when I had a varicocele. I too wanted bigger balls and started researching and implementing these things. I did have a heart issue in past but think the herbs and other supplements caused the increase and not the past heart condition.
Also after you ejaculate, be sure to replenish your body with vitamins and minerals especially zinc.
I got some of this info from a program online I think it was called big natural testicles. Would provide more refs but have to go to work now. Large blessings in your journey!