Kundalini awakening is an attractive concept. Many contemporary meditators, in particular in the west, are mesmerized by it, attracted by it, tempted by it, or actually started their meditative practice because of it! Kundalini awakening as described in some modern classics is quite explosive, frightening and unexpected. These writers are usually self-learners. And when some of these self learners later become great teachers themselves, they recounted such experience in their books. Of course those poor guys who, as a result, suffered some traumatic side-effects will not be there to tell their stories.
Nevertheless most of such mentions said that if their awakenings could be better managed, the result would not be so shocking. And with the benefit of experience, their students can avoid such drastic encounters. It is interesting to note that there are cases of Taoist meditation practitioners, and self-learners too, who said they experienced such experiential shock. The Japanese Taoist master and popular writer 高藤 聡一郎 is an example. In Taoist practice, a mild energy surge is called arousing chi foundation (動氣基). Explosive ones are labeled as chi deviation, in a negative sense.
What was mentioned in those experience is a form of sudden explosion of chi energy. It is just like a dam suddenly broke open. Why is it so? And why a more controlled training can avoid this?
When chi gradually builds up during training in a more controlled training, the student will be trained to open his blockages step by step at the same time. In this way, when the chi become massive, almost all blockages have been cleared. And this is safe. However, with an eager practitioner who is unfortunately without the proper guidance of a good teacher, he may be building up his chi without realizing that his internal blockage is being pushed into a thick wall, disallowing his chi to pass through. Failing to see progress, he became more eager, and engage himself into more vigorous training. Eventually his thick blockage exploded open! His pent-up chi rushes upwards to his head. The experience will be shocking, and painful, and with possible long term negative effects.
There is however in some cases there will be a positive side benefit. This shock can result in a near-death experience. And with (most of the time unintended) prior mental or spiritual training, this can result in an Enlightenment with a capital E. The second Patriarch of Zen Buddhism was reported to have an Enlightenment experience immediately after he cut off his own arm!
For most modern students of kundalini meditation and Taoist meditation, the highest level of Enlightenment is not a training objective. A gradual method is the best method for their training objectives. And therefore it is absolutely no need to try the shock-therapy route. For those who are truly religious or spiritual, they should find a proper teacher rather than dangerously experimenting with shocking kundalini awakening through explosive massive pent-up energy.