As one practices more and more, things will change. There will be new or related developments. The problem is that we heard of kundalini from yogis who advanced only with spinal kundalini. There are many diagrams in books and media with that. Once in 1970 while I was in the Philippines, I found a small book at the library which discussed front kundalini. The writer from India, stated that it was ridiculous that only spinal or sushumna nadi kundalini is mentioned and known. He said there is also front kundalini. I would state further that there is sides kundalini, middle of trunk kundalini and many other kundalini spreads which occur independent of spinal kundalini.

In one book, Yogeshwarananda even said that there is no kundalini in the subtle body. Hence it is that what we know from standard books of yogis from India and elsewhere is merely part of the scan of kundalini.

Hence one should be open minded to learn more and more as one practices. One should expect to stumble upon or to discover and to be inspired in new developments which are unknown or undeclared by previous teachers.

In the past due to the non-prevalence of writing, yogis made no notations of their experiences in pranayama practice and meditation. There is a dearth of information about that. This may mean that even though they experience many other types of energy arousal, they just did not mention it to their disciples. They certainly did not jot it down. Many great yogis were illiterate anyway and that was no cause for shame in the eras before writing was required for most people. In fact, literacy as we know it today does not automatically make anyone a yogi.

The development of the various kundalini formats come about according to the evolutionary status or previous yoga practice in former lives of the specific individual. This means that for one yogi, something will be experienced which may not be experienced in the same way or in the same context and practice sequences of another yogi. This is why it is a farce to institutionalize and standardize the process.

Your experiences as described are from spinal kundalini specifically from the base chakra as it spikes out through the thighs on its journey out of the feet into the earth. The experience is sensational and shows that your practice is developing into advanced levels of the practice. In time you may experience kundalini in remote parts of the body which occur without reference to spinal kundalini.

I am sure that if you looked through the diagrams in my books, especially in the inVision series, you will find a diagram which shows what you experienced. But it is not always possible to have a more advanced yogi, verify the experience because a student may have a strange weird experience which the teacher just did not have.

It is also a fact that anyone who had sexual climax experience may have experienced a spike of kundalini running through the thighs except that instead of striking from the muladhar base chakra, it spiked from the sex organ chakra, which is not the same as the sex chakra on the spine.

Failure to know or experience this during sexual climax experience would be because the experience occurred from masturbation rather than from coitus or sexual union with the opposite sex. Or it may be because of the pleasure experience fragmentized the objectivity of the person concerned where that person could not discern the circuity of the pleasure energy spread during the experience. If someone is blinded during a lightning storm, he/she cannot tell where the lightning occurred.