Whole-Body Kundalini
Whole body kundalini is different to spinal kundalini arousal. Spinal kundalini has to do with sushumna nadi spinal arousal into the brain, where the core-self finds itself in a bliss force which is scattered spiritual light. Most of this experience occurs in the head of the subtle body.
Whole-body kundalini occurs due to cell kundalini arousal, where all cells in the body come alive simultaneously after a spread of neutral bliss energy happens while doing bhastrika/kapalabhati breath infusion. The entire subtle body, not just the spine or head of it, becomes involved in the arousal. Instead of keeping track of what happens only in the spine and head, the yogi must be attentive to the entire body, particularly what happens in the trunk of it. The yogi finds that as the core-self he must look down into the body and manage the energy.
The conventional muscular contractions like the anus lock, sex lock, navel lock, neck and mind locks are insufficient for regulating whole body kundalini. With that the entire body acts as a lock as a tight compression envelope or balloon in which the aroused energy is contained, so that the bliss force which burst out is compressed in on itself over and over.
In one experience it happened suddenly but as I was already looking down into the body, I did not have to shift focus from in the head to the trunk of the body. However the envelope/balloon shape of the subtle body tilted forward as if the body would topple over. I managed to stabilize it, center it and keep it upright. Then there began a jingling of energy, like transparent stainless steel springs rattling up and down through the right and left sides of the trunk of the body. This was as if the springs were hanging from the collar bones and jingling down and up through the trunk of thighs. Then in the middle at the groin, I noticed a rectangle transparent crystalline form dangling down, expressing neutral bliss energy. This lasted for a time.
Srila Yogeshwarananda observed this as well. He said that it was because of lifting the reproductive hormonal energy out of the pubic area, causing the subtle body to become altered as a yoga siddha form.