Slavs are best in swearing :D Germanic languages are not that inventive in that way as Slavic are. In Slovak there is nice word “pičofúz” …I dont even know how to translate it, something like cunt beard :D or “kokotský kokot dokokotil kokotinu” and that I really cant even translate, I can only tell you that, kokot is dick. Also offending friend as Dušan said is common here as well, for example “nazdar ty buzerant”, what means hello you gay.