There are many forms of Yoga in India – most are not known or practiced in the West. Jnana Yoga (the Yoga of discrimination, as with Shankara and Ramana Maharshi) and Raja Yoga (the Kingly Yoga of eight sections) require long years of training from a true guru, whereas the little bit of Hatha Yoga (Sun-Moon Yoga, one of five preliminaries of Raja Yoga) that is taught in the West is often taught by inexperienced teachers after a few weeks of training, thereby increasing very real dangers.
I have heard westerners say they teach Raja Yoga, but when I ask if they instruct in Pratyahara (fifth of the preliminaries) and insist on Yama (for social development) and Niyama (for personal development) for their students, they don’t know what I’m talking about. Actually, I do not know any western teacher who knows how to teach Pratyahara (the withdrawing of the senses from the field of the senses, thereby immunizing the Yogi from pain), though a few may bluff and call it “interiorization,” an abstract, general term.
Quite a few of the Yogis I lived with in the Himalayan foot- hills practiced forms roughly subsumed under Kundalini Yoga, and I saw one, without a teacher, who went out of his mind. Meditation or Mantra Yoga was almost always a necessity for their practice. They generally followed sadhanas given them by their gurus.
Those doing Mantra Yoga were given their mantra in initiation by their teachers. Only a recognized Yogic Master, usually of a particular tradition, has the right to give such initiation – this is a must – and it carries on the teaching and tradition of the originator. True gurus are even stricter than Zen Masters, and one does what he or she is told or is sent packing. I saw it happen in the Himalayas, and a rather tragic man, who had been a successful lawyer in Lucknow before becoming a Yogi, was thrown out of an ashram with no place to go. I gave him the small amount of money necessary to take a bus to Dehradun (where he might pick up a patron who would place him in another ashram), but I have no way of knowing how his life turned out. He was never meant to be a Yogi, but gave his estate to his family when he reached the age of 50 and tried to follow the ancient scriptures in retiring from the world.
Those who initiate or pose without the right to do so are incurring serious karmic debts. Although I was initiated into one of the great traditions of India, and asked to work for them in that country, I have no right to initiate or give a mantra. There are dangers inherent in various Yogas and the seeker must be careful to be led by those competent to do so. As is true with martial arts, it takes many, many years of untiring labor to be ready to be a Yoga teacher.