If you can freely vent your feelings already, it may take only 30 minutes or an hour to discharge the emotions. You may act mad or sad on the surface without feeling intensely in your gut. Intense, complete expression is necessary. You may not take the task seriously, especially when with a friend. Joking and playing around is a way to avoid a scary, serious task.
Some people are afraid or ashamed to cry.
The idea of losing control is scary. Completely out of control, hysterical expression of intense emotions should be avoided, unless you are supervised by a professional. Occasionally, a disturbing thought or feeling may occur to you. Some people object to expressing emotions by using cuss words and obscenities. You should use whatever words are naturally expressive for you.