I normally teach most drills at a safe distance to begin with and then close the range once students have the mechanics understood and the control not to actually smash each other. I like the DP clip posted and the only thing that I would say isn't covered (most likely because he talked about it elsewhere or some other reason) is that the partner doing the striking, whether the palm strike or the punch should also be learning to switch off their attack once it has been intercepted / deflected