The procedure is typically as follows...

1. The doctor spends two days forcibly dialating the mother's cervix.
2. The doctor uses forceps to pull the baby's legs down; rotating the baby so its head is away from the birth canal.
3. The legs & body are pulled into the birth canal, until only the head, which is too large to pass through the cervix, remains in the uterus.
4. The doctor uses a sharp instrument, such as scissors, to puncture the base of the baby's head.
5. The doctor inserts a tube into the hole he created in the baby's skull and suctions out the baby's brain, allowing the baby's skull to crush and pass through the cervix.