Man... I'm guessing these are high schoolers?
I wouldn't try to hold them to too high of standards. I'd tell your brother that he should maybe try to stick up for you instead of being a little twerp, but other than that there isn't much you can do. It all goes back to the more you struggle the more they'll laugh. Don't let them get to you or they'll know they can get to you. Be stronger than them. Be more mature then them. Walk away from it and go have f-ckin bangin sex with your girlfriend (or something like that) to regain some of your manly feelings.
Just remember there will always be supreme jerks with lots of friends. Its a classic character type. Keep to the people who support you, and f-ck the rest.
I knew this one kid in high school who was such a douche. White trash in the worst ways, school mandated anger management... the works. I never liked him. Eventually he started dating my best friend who I was in love with (and that I later went on to date for 3 years). I still had to see him almost daily(we went to the same school and shared friends) and be somewhat genial. I was even somewhat nice to him in a jokey-douchey kind of way when he came by my work (local fast food joint by the movie theatre). These are just things in life you have to deal with.
(also, if you tell someone to suck a bag of dicks... they may be more likely to say something like that to you then if you just don't respond at all or pretend that their comment did nothing more than bore you. Don't give them ammunition.... and setting his comment up perfectly by using dicks in your initial insult wasn't the best planning on that either. Before getting in a debate with the immature I'd study up on some classic quick-witted comedy. If you're good at that you'll almost always come out with the upper hand )
