Master Chen Zhonghua Online Lesson on Dec. 31, 2021 - Kelvin Ho
Increase speed in the same direction.
Six Sealing Four Closing - First break the elbow, if that fails, yank the whole arm off the shoulder.
Machine gun exercise - Twisting the towel
Do first 13 with speed, one move at a time.
When you practice intensively, don't go overboard. Take a break before continuing.
Source: https://practicalmethod.com/?p=87849