Before the Practitioner begins his practice he must receive initiation into the mantras, without initiation the mantras are often in the best case powerless or almost powerless, often though mantras which are used without initiation actually cause a negative effect on the being.
Before receiving a mantra the practitioner must be examined either directly by meditation or else by remote means accessible to the guru, after an examination Of the student a fitting mantra can be given to him. This mantra is individual and must be kept secret, the power invested in the mantra is given by the guru in a certain measure this measure is designed to be enough to create the effects necessary in the practitioner, without it being too much, if the power given with no limit adverse physical, energetic, emotional and mental reactions will occur, as each individuals system can only deal with a certain amount of energy at certain time. By disclosing the mantra to someone else some of the energy of it is transferred from the initiator to the initiated, and so if the initiator is not strong enough he will render his mantra too weak to create any effect.
Since each individual is different from another, each individual will receive a mantra which is suitable for his structure. The same mantra that is a life giving elixir for one practitioner can act as poison in another. Very much so in the same way that an injection of insulin can save the life of a diabetic patient but kill another who is healthy.
The human being is a manifestation of the divine consciousness, this is always present within him however his structure might not be able to express it. Those causes which prevent this from being are usually termed in tantra “blockages” or “impurities”. In most case these blockages are removed by the same mantra that is given to one to raise ones kundalini to the sahasrara, and it removes these as it rises. However, in some cases such blockages or impurities are deep rooted and profound, and they are usually the cause for the failure of some practitioners to experience the effects that the different yoga and meditation techniques and teachers claim to give. In these cases the system is simply not responding to the technique as it normally should. And so such a practitioner may practice for years and achieve little, not knowing what he is doing wrong, or whether his teaching or teacher is a true one.
In such cases one is given a preliminary mantra that uses kundalini to specifically address these issues, this mantra is usually used for a short time after which the problems resolve for good and need not be invested upon further, the practitioner can then continue with the full tantric sadhana for raising his kundalini and level of consciousness, or can return to his regular previous practice and for the first time observe the desired effects happening within him.
While the full initiation requires a direct contact with the guru, in most cases a partial initiation can be imparted by the guru remotely. And so one does not need take the arduous journey to meet the guru without having first experienced the efficacy of this practice.