Dr Paul Lam’s Introduction to Tai Chi for Energy
In this form Dr Paul Lam uses a mixture of Sun style and Chen style T’ai Chi to compare internal and external energy and then follows with an introductory lesson.
If the video below doesn't open then watch on YouTube here:
https://www.youtube.com/watch?v=i4eX13rNG6o
There is also a forward facing and backward facing demonstration respectively by Gladys Tan here:
https://www.youtube.com/watch?v=AQFDSEDIHco