Warning- cussing

Ok so when people insult me this is how it goes, they'll say something like "you're a bitch" or "you do realize ur a idiot right?" And here's what I'll say. "I know". You cant insult me with stuff I already call myself. That's not how this works. I mean it still hurts but not as much as it should. So im fine with people insulting me.
    
But, the second one of my friends or many of my friends is insulted then thats when I become pissed. I will chew someone out and totally destroy them before one of my friends is hurt emotionally or otherwise. I don't care who you are or anything. Dont mess with my friends.