What was Tyson stretching here?

[SugarBoxing]

https://gfycat.com/PhysicalTheseJellyfish

@ all fitness experts and @Scrap

What do you think?

Stabalising His lower back and groin, but not a good way.

I thought lower back is here:

https://gfycat.com/WetWeeklyDromaeosaur

What do you mean by

1. Stabalising? Why do we need to stabalize anything while stretching?
2. why lower back and groin?
3. why not in a good way?
4. what is the way?