My friends make fun of me but when i make fun of them they get mad?

Ok so I can take a joke even if it is racist even though it pisses me off, i dont really get mad because if its a joke your not supposed to take it seriously. So one day one of my friends made a racist joke about me and i just laughed it off like it didnt happen. Today me and my friend were arguing sorta and i called him big and he took it way to far. I just wanted to know why they think its ok to make fun of me but when i say something to them its not ok? Its not just him a bunch of my friends do it. Im a sophomore in highschool if that helps at all. I know people change in highschool but it just makes me wonder if you can make a joke why cant you take it? What do you think i should do in a situation like this? make some new friends?