Although I regularly sit on my balls, I rarely hurt them. I have enough loose skin in my scrotum that they just pop out of the way. It is like trying to grab a hard boiled egg with buttery hands.
My balls hang low enough that, when riding a bicycle in shorts, I can let one hang on each side of the saddle, with my cock resting on the horn of the saddle. I prefer to let the whole lot hang down one side though. I must just be careful that it does not show too conspicuously in case someone coming the other way looks at the leg of my shorts. I don't mind if they see flesh inside my shorts but I don't want it all waving blatantly in the breeze.