Have you heard of this meme that men can't sit cross-legged because of their genitals? Are you possibly affected by this problem yourself?
I used to sit cross-legged all the time in school and got bullied by some kids who took it as proof that I have no testicles. I also heard men complain in earnest about how they can't sit cross-legged without hurting themselves.
Is underwear the issue here? I have always worn boxer briefs that cup my balls nicely, maybe they never get in the way of sitting because of that. Do loose boxer wearers have this problem? Or is something else the issue here? Individual anatomic differences, sitting technique...