Here is an example of what you can learn in JojaFlex. This short video shows how to start working on your side split. You can also read the explanation below.
The sidesplit consists of A) bending your hips (flexion) and B) abducting opening the legs (abduction). Many people push their shoulders forward for the illusion of hip flexion. However, this is not the same as bending your hips. And you will not improve. So what to do instead?
Start in a position that allows you to have a long, ‘straight’ back. Don’t be afraid to start leaning backwards if this is all your hips allow at the moment.
Once you have a proper starting position of your hips and back, you can start working on opening the legs. Briefly bend your hips a little extra, come back in your starting position and repeat this a few times. Then open your legs a little by pushing them to the side or pushing your hips forward. Repeat these steps until you feel you have reached your maximum.
If you combine this with strength training in your newly reached range, you will increase your range of motion. In other words, you will gain functional flexibility.