In Pilates class, we do a lot of work in “neutral pelvis”, that is when our hip bones and pubic bone are level. When I ask you to place your legs “hip-width” apart, I mean in line with the hip bones at the front of your pelvis. When seated, I ask you to feel your weight pass through your sitz bones.
This diagram shows you where these bones are. When you can find these bony landmarks on yourself, you will be able to improve your alignment during class and your general posture.