She is holding the extension hair against her own and twisting them together, and doing the same thing to the other strand and then cross them over. It's basically the same twisting method I've been trying to explain for my 2-strand twists. I don't just cross the two strands over. I first twist them separately clockwise then cross them over each other anti-clockwise.
It's the method I try to demonstrate
here.
And you use that same method all the way to the end. It's not so obvious that she is actually doing that to the end of the twists because she's moving fast, but also because after she gets beyond her own hair, it's not necessary since her extension hair is already "separated". Twisting the section of the kinky twist that contains your hair (or twisting your own hair if doing regular 2-strand twists w/o extensions helps to keep your hair smoothly tucked away tidily into the twist strands) so that the end product is "clean". The twisting doesn't have to be exaggerated as the demos show. It is only a small turn to keep all hairs in that strand "together". I am doing the same twisting all the way to the end
here even though it's not as exaggerated as in my previous demo.
The results are smooth looking twists that hold through several washes. It's the method I used for t
hese regular 2-strand twists that are 4 weeks/8 washes old, and that I can
undo with ease w/o any knots or tangles.