The core of the Celestial Yin Sutra is similar to its counterpart, the 'Bane of Yin' technique.
The female practitioner has to concentrate her Yin from all the Yin prominent organs to the insides of her 'yoni'. And when she connects herself while touching her flowers with another's, the two Yins connect through the love-hole canal.
However, unlike the normal case scenario where the Yang of the male can attract the Yin, the Yin from one body could move into another's only while being pushed by an external helping energy.
That would be stellar energy.
The two women would push the Yin from their bodies into the others, making a complete loop of Yin essence while connected in a scissoring pose.
This continuous loop has to follow a predetermined path throughout the bodies of the two women; only then can they interact properly, resulting in the proliferation of the Yin essence in both of their bodies.
