I can stretch my balls to my bellybutton

I am not sure exactly how I found out that I could do it, I think it was a dare, but I can literally stretch my balls and set them in my bellybutton. I noticed at a youngish age ,15 or16, that my balls hanged extremely low. I have asked many of my friends and none of them can even strech theirs a little with out it hurting. Does anyone know the reason behind my unique ability.