Walking upright, pushing the head upward as if it was suspended by a rope. Not much increase in lumbar hollow.
Do not seat curved on soft chairs. Whenever possible, sit with the pelvis on the very back of the Chair, with the lower back supported by the chair.
If the mother leans forward, allows the infant to find a better position.
If your baby is breech or his rear back, try to be every day some time in a four-legs position.