I too have the problem of extremely big testicles and I can agree with all that others have written. Mine are so large and the sac correspondingly so that it is possible for a "growth" to hide for a while. So frequent self examination is required. I know this from experience. Because mine are so large, a few years ago they were able to "hide" a mass nearly the size of a tennis ball until I discovered it one morning. It is true. Your heart really does skip a beat. It has not been there a few days before but now it was. I dropped everything on my normal schedule and was outside my doctors office when the door opened that morning. Fortunately, a simple exam in a darkened room with a flashlight revealed that light passed through it, and it was therefore benign. My heart restarted and it was amazing how long you can go without a heartbeat or breathing. LOL The medical term is a spermicile. It was explained to me that my body was making so much fluid, that it needed another place to store it all, so it created one. That was what the first doctor told me. He also told me to have more sex and see a urologist if I wanted it removed. Yes, I did, so after a few hours of research I made an appointment to get on the schedule of a board certified urologist, who was on the local medical school faculty, had been practising for over 30 years, and was the senior partner in the largest urology clinic west of the MS river. He examined me within a week and actually found that one spermicile and several smaller ones, and then a week later the spermiciles were removed. The positive thing was that I learned to check myself daily, and that I now see the urologist for an annual checkup with him.
I have always had the problems of sitting and clothing and it being very apparent, despite my best efforts and camoflage with clothing and such, that I have extremely big balls, and I have the problems of keeping them, safe, warm, and dry like others. How I sit and other things are rote to me and automatically done. Still, I did learn you have to check them often and well and be diligent about that too.
My best to all.
Ben