I think if your a fat ****er it will hurt you balls because you have fat legs to crush your balls (Or if you have big muscular thighs). If you're skinny then you have more wiggle room for your balls. Then you get the people who say "it hurts my balls" to make them look "hard", in school yard talk, and as though they have a big dick and balls. It's like calling men gay when they do the splits. That hasn't anything to do with your dick. You just need to stretch your muscles, hence why many martial artists can either do the splits or kick above head height, legs stretched and hold it. Loads of people cross their legs, including actors. But the ones who say it hurts are the ones who have fat legs or want to brag.