Shoulder opening:
To put it bluntly, let your shoulders reach behind your shoulders as far as possible under the condition of natural relaxation. Try to get your shoulder blades together. Just like the model on the runway, hold your chest out and try to show the neck and below the clavicle.
Method 1: Put your back against the wall, make fists with both hands, close them and put them on your waist, but stick your ass and back to the wall. Please press your shoulder against the wall as much as possible. This is the best way to open your shoulder.
Method 2: Face the wall, preferably stick it on the wall, grab it with both hands and lift it up, then ask someone (preferably someone who has practiced dancing) to put his knees on your back and pull his hands back.
Open your crotch:
Simply put, it is to pull the ligament on the inner thigh.
It's best to press leg press before practice. It's a warm-up and it's not easy to get hurt.
Method 1: Hold the bar (or railing) and squat with your legs open. When squatting, try to open your legs to both sides and keep your heels together, preferably in an "I" shape.
Method 2: Facing the handle, buckle one leg frame upside down on the handle, and the sole of the other leg stands in the shape of "I". Stick a pole on your hip.
These methods are the basis of practicing dance. No matter what kind of dance you need, practice slowly and don't overwork.