I have an Irish friend and I call him an alcoholic, a traveller and a pikey, and make jokes about him eating dogs and having sex with his cousins all the time. He doesn't mind because he knows I am his friend and I myself had part-Irish grandparents. I also had part-black grandparents, yet if I made jokes like that to a black person they wouldn't accept it and would probably hurt me or call me a cracker or something.