In fact, never touch a student. You can be liable for touching a student unless it is in self defense or you are trying to stop a fight. Always seek help from a nearby teacher in situations like this. If you are very angry, try the silent method and try to gain control. Appear relaxed and speak honestly about your expectations in a firm but quiet tone.
Some students respond best by being talked to outside of class.
It's not a good idea to do this outside of your own class because, for obvious reasons, you must never leave your class unsupervised. You could try seeing the student after your class is over so other students from the same class don't notice. Students are more receptive if they know other students are not watching or listening. Also, they won't have the temptation to show off in front of their classmates. It's is so important to learn your students' names quickly and learn the correct pronunciation of their names.