Stretching is not for everyone! If you have any problems with your hips, back or knees be careful, and the best would be if you would ask your doctor first, if you can do any flexibility exercises!
While stretching there might be pressure which can be really dangerous! So If you feel pain or something is making you concerned give youorself a break. You won't stretch your body in one day. We are talking here about MONTHS or YEARS of trainings which can actually improve your flexibility a lot(still you probable wont be able to do some hardcore moves like that one:
but still you can be better than you the day before :) ).
But patience is really the most important here.
Patience and persistence!
If you've never done any kind of flexible training before start with some simple things.
Here is a really nice movie by emotioncatcher, who is pole dancing and hooping, she did movie for pole dancers about stretching, but it will be great for aerial hoopers too:
I can guarantee that if you will stretch your body everyday the effects will be really fast!
So move your ass and stretch! :)
One more important thing:
YOU CAN NOT STRETCH WITHOUT WARMING UP YOUR MUSCLES!
So you have to remember about WARM UP! It might be faster than regular one for trainings, but you have to do it.