I'm not sure what to do aside from trying to break this down move by move.
so here it goes:
partner 1 and 2 stand close enough to hit each other by about a fist or two.
each one in IRAS.
partner 1 places a punch upon partner 2s chest which is done with a step, partner 2 than pak-saus the punch hitting the outside of their arm, (left on right arm, or vice versa) than partner 2 strikes at partner 1s hip.
partner 1 than gan saus and shifts from left legged stance to right, so that s/he is now standing on the right left and facing the other direction, as this is happening s/he also throws a punch on centerline near the chest.
The punch is intercepted by partner 2 with a tan sau, and he shifts from left leg to right leg, also changing directions, and also throws a punch towards the chest. Than it repeats, the pak sau loops at this point.
all of this is done with stepping, you pretty much make your way up and down the room in a straight line going to the side.
I was told it is to learn flow, and give a concrete example of using received energy to add force to your own strikes.
Hopefully this makes sense lol, sorry it took me so long, life has been hectic, and we have sifu micheal casey coming out soon, been busy practicing and working. cheers!