How do you know every boy in your school wears boxers? Sure, it's not nice to be bullied about your underwear of all things, but the reason they bully you in because they're insecure and they've cultivated a culture of rules, and those who don't fit in with them get rejected. Boys don't like wearing briefs because they're afraid of them due to made up associations such as briefs being for little children or old men. You or anyone else who has found themselves in your situation can bend to the will of bullies, but personally I'd keep wearing them and they'd have to like it. If you want to give bullies a win then give-in and wear boxers. I know you actually want to wear boxers, but wear them because you want to, not because the bullies are forcing you to.