Refining the Mother and Child Ghost required caution. It also had to be done slowly. The process might take a long time, but persistence would surely bring rewards.
It was Mahali's first time encountering a Mother and Child Ghost, so he was extremely patient during the initial refinement. The first time, he merely fed his Yin Sha Qi into the jar for the Mother and Child Ghost to absorb. His own aura was mixed into that Yin Sha Qi, which was the first step in refining the Mother and Child Ghost: familiarizing it with him.
The Mother and Child Ghost needed Yin Sha Qi to exist. Once its Yin Sha Qi was exhausted, its true form would disperse as well. Therefore, when the Mother and Child Ghost was weakened, it would automatically seek out Yin Sha Qi to absorb.
Thus, refinement meant waiting until the Mother and Child Ghost needed Yin Sha Qi, then having the Sorcerer provide it—with his own hidden addition mixed into that Yin Sha Qi.
This way, while absorbing Yin Sha Qi, the Mother and Child Ghost would also absorb the Sorcerer's own aura. The aura mixed within was not much compared to the Yin Sha Qi, but it could gradually familiarize the Mother and Child Ghost with the other presence within that Yin Sha Qi.
Once the Mother and Child Ghost had become accustomed to his aura, he could proceed to the next stage of refinement: merging his aura into the core of the Mother and Child Ghost. That would mean the refinement was nearly complete.
Merging it into the core was essentially controlling the Mother and Child Ghost. But before doing so, he had to make the Mother and Child Ghost thoroughly familiar with that aura and ensure it did not resist. That was