Kiss of Kundalini
When raising kundalini using kapalabhati/bhastrika breath infusion (pranayama), it is conventional for the kundalini to enter the head and go through the subtle head to penetrate the brahmrandra opening which is at the crown of the head. Even if the crown chakra is not open or seems to be non-existent, the kundalini, if it has a sufficient charge of energy from the breath infusion, will reveal the crown chakra.
It may even create it if it is nonexistent or if it is entirely blocked with dense astral energy. This could be compared to a pipe which is blocked by sediments and mineral deposits and which is cleared with a powerful blast of water which has so much force that it pushes the deposits out with jet force.
When the kundalini enters the subtle head in that way, it first goes to the intellect which it infuses. Then those two adjuncts are unified with the core-self which finds itself to be in a white-golden light but without contact with the physical body. The physical body is still present but the connection to it which causes the core-self to identify itself as the son or daughter of this or that parent, is broken for the time being. The core-self then has no experience of the physical body and cannot identity itself as a social unit in the physical world.
Fortunately, this does not last for more than seconds or a few minutes, except in rare experiences when it last longer. During the experience, the physical body is usually reclined or lays somewhere somehow, breathing at the slowest possible rate.
The kiss of kundalini however occurs later, after repeated rises of kundalini through the spine into the brain. This happens when the kundalini learns how to love the core-self more than it loves the intellect. Initially the kundalini goes to the intellect when it enters the head. This is because of its attachment to the intellect, which is more than its love for the core-self.
However later in the advanced practice of raising kundalini, when the student can cause cell kundalini to be activate and is no longer dependent on spinal (sushumna) kundalini, the kundalini energy comes up through the entire neck not just the spinal passage. In other words, the neck itself becomes the sushumna when this happens kundalini enters the head and goes to the core-self and kisses it.
This is experienced as the sweetest possible kiss the core-self could get within its psyche. It happens just on the inside of the crown chakra. Instead of bursting out into the astral environment through that chakra, the kundalini remains on the inside of the crown chakra and kisses the core-self there. This is quite a love affair between the core and that adjunct.
Because it is attached to the kundalini and feels itself to be the lawful spouse of that adjunct, the intellect for its part, feels some slight jealousy when this occurs.
