I didn't see any real, hard sparring. At least, Sifu Sergio is discussing applying these concepts in sparring.
Published on Mar 25, 2017
The IWKA way of sparring in internal Wing Chun (IWKA Wing Tjun system) using yielding and adhering and at a more advanced level sticking to seize:
https://www.youtube.com/watch?v=XkKlJMIjw4I