Moxibustion is related to acupressure - it involves burning two incense sticks to heat accupressure points on the sides of the feet. It can help as well.
It can be used elsewhere for different things too (I had moxibustion / acupuncture for induction, and have used moxibustion in conjunction with acupressure and remedial massage for a neck strain), and is often used in conjunction with another form of therapy for best effect.

There are pressure points for induction of labour in the ankle (just below the ankle bone), and in the side of the little toe, which is why these areas are avoided in massage in pregnancy, except when trying to induce labour.

If your sis is booking a therapist (massage/acupuncture or acupressure), get her to make sure they are experienced in induction of labour.