Stay OA, Ok?
What is "the most practical way of making sure my baby stays anterior? I've had TWO posterior babies! UGH!”
Mainly, the baby will "stay" anterior if your womb is balanced (symmetrical, not torqued or twisted) and you continue to use good maternal positioning. Positioning without releasing tension in the abdominal soft tissues and pelvic joints isn't likely to succeed in rotating a baby in pregnancy, especially for a woman with a history of posterior babies or breech, because these positions show the uterine ligaments weren't in balance before pregnancy.
If you have a history of OP then you may have chronic tension in places you cannot will away. It may also be that you have a pelvic shape that makes it hard for a baby in late pregnancy to swing out of an OP head position into the anterior or Left Occiput Transverse position. But this comes after the first cause, twists in the ligaments.
Women with a smaller version of the triangular shaped brim (android pelvis) need to help their babies’ position in the second trimester of pregnancy.
If it is your third trimester, then begin with the inversion for 30 seconds a day; get some body work on your pelvic joints and abdominal ligaments ASAP; and follow careful maternal positioning. Homeopathic or acupuncture can also work wonders.
A few mothers who use OFP techniques carefully and consistently have babies that seem to return to the right occiput posterior position after a couple of days of being on the left.
Two things may be happening. One, the baby really is going from the mother's right to left and back again, or back to front and back again, including the head turning with the body. This is considered normal, but I think that it is not. Further more, I think it is unusual.
More often it is just the body of the baby changing position while the face continues looking forward. The neck bends so that, instead of turning the head to look over one shoulder and then the other, the baby's body does the turning and the head stays still.
This can happen in a woman with an android (triangular) pelvis. Inversion is helpful to help the baby lift his or her head up out of the pelvis a little bit so that they can turn and face the mother's right hip. The baby is turning to try and turn the head to face a hip, or in the case of a woman with an android (triangular) pelvis, to face the right side of the tailbone (in the sciatic notch).
A mother may need to wear a pregnancy belt to give the lower uterus a lift. The slope of the lower abdomen may have collapsed due to weak abdominal muscles. This can be from carrying many womb-babies. When the stomach muscles are weak in a first time mom it may be from being very sedate during adolescence, if there isn't another obvious reason, like surgery on the ligaments or something unusual like that.
For mothers with good uterine tone that experience frequent fetal position changes or whose baby stays immobile on the right side or stays direct occiput posterior, the maternal inversion is very helpful. Tone is not about muscle strength - its about fascial freedom. Symmetry or Balance is the key. Read more about this in The 3 Principles of Spinning Babies.