The first 37 seconds show three moves-for classes 8-10 so you are getting a preview of Defense in Disguise and Cross Hands
Punch with Parry
Part One:
You are on the left substantial side. Roll back to your heel and set up a 45% angle with your left foot. As you do this, make a pulling sideways movement but with your right hand in a tai-chi fist, palm facing the ground. Step forward, cross the center line, turn the waist, and as you do so, strike the opponent’s noggin’ with a backfist. Your right fist will end by resting on your right hip while your left palm will come out as in brush knee twist step.
Part Two:
Step forward on the left side, cross the center line, turn/loosen the waist to the left and as a result of this softening motion, come forward with your right tai-chi fist. Your left hand/side will follow your waist movement and should be upright near your chin or wherever it lands to protect yourself keeping the shoulders down.
Tai-Chi fist (The four fingers touch the palm and the thumb rests across the forefinger and middle finger equally) The fist is always relaxed; solid but soft. You should not feel your tendons in your arm tighten or feel your joints squeeze. Your fingertips should graze the palm equally.