Divided into the top eight and the last eight. Let me give you a simple lesson:

First push the right hip forward to the right, then take the left hip as the axis, pull the right hip backward to the right, then push the left hip forward to the left, and then pull the left hip backward with the right hip as the axis. This is the back crotch.

The first splayed buttock is reversed, the right buttock is pushed to the right and then rowed forward, and then the left buttock is pushed to the left and then rowed forward.

Practice unilaterally first when practicing.