you can do many things. ignore them. Tell them that their being rude and need to stop. you can tell someone about it.
Learn from your mistake and move on.
Tell him that if he doesn't stop being immature, than you're going to leave him and find someone that treats you right.
What you do is you stop being friends with that person, or tell someone that you trust.
Here this is what you do: Tell them and stop being an emotional train wreck.
LOLWUT? But seriously, you could tell them to stop or do what nobody ever likes to do and tell someone like a teacher or something...
First, you should tell an a adult if you see someone being bullied or is being bullied Note: STOP BULLYING
tell your mother or father (or leagel guardian) maybe they can get them to stop(and yes that is very gross)
simply and politely say stop calling me and tell the reason why.
you go up to them, punch them in the face, and say "dude! cut it out." then run away.
be mean and tell them they will have no chance with you and to stop with their sick fantasies of you.
You stop them and tell them that what they are doing is wrong. If there a hurting someone of color then you should lead that person away and stop the fight.