Our arm swinging can be used flexibly. For example, when we tightened the motion of the arm and use the strikes consecutively it becomes a thrusting finger attack or Biu Jee as it is known in Wing Chun.
Master Leong called this White Snake Spits Poison. We normally pair this with footwork while attacking in an elusive manner. Since we are doing a sitting down lesson obviously stepping is out of the question.
My non-Ip Man Wing Chun teacher said that Biu Jee is a form that teaches a certain principle of attack. This video gives a cursory example of what an attack using this principle can be like.