"Be carefull when discribing the ladies Throwaway. The step is not back. If it were contact of the body will be lost. The side will be too open. Best to go back to the pictures and check which parts of the lady is still in contact with the man."

Since you had expanded the discussion to generic backwards actions, I was making a generic point: the lady must not tilt her pelvis to position her leg. Nor may the man do so.

In a throway, as in any other situation, both dancers must endeavor to keep their pelvis aligned with their torso.

It's not physically easy, but it is conceptually rather simple.