First of all, sit on the ground with your waist straight, your legs together and straighten forward. Then, slowly spread your legs outward until you reach the maximum. Let others pull your leg out, a little bit a day, don't straighten it at once, or your leg will hurt. Thin hips are very useful.

Lie on the ground with your legs over 90 degrees and open in a crossed position. My legs should be relaxed and my crotch should be relaxed. It took five minutes at first, and then I gradually added more time. The longest time I spent was 40 minutes, which was very painful, but if I persist, I will definitely achieve something. Be careful not to support your legs with your hands. After you finish, you must kick your side legs and hind legs, or you will lose your muscles.