Even anyone living a free lifestyle without the formal rules of yoga, if he practises vajroli well, that yogi becomes a recipient of siddhis (perfections).
Vajra is 'thunderbolt' or 'lightning'. It is also the weapon of Lord Indra and means 'mighty one'. Vajra in this context refers to the vajra nadi which governs the uro-genital system. It is the second innermost layer of sushumna nadi. Vajra nadi is the energy flow within the spine which governs the sexual systems of the body. In mundane life it is responsible for the sexual behaviour and this aspect has been termed 'libido' by Dr. Freud and as 'orgone' by Dr. Reich. In tantric sadhana this energy is not suppressed but is awakened and redirected. OH mudras (vajroli, sahajoli and amaroli) are those which specifically sublimate sexual energy into ojas (vitality) and kundalini shakti.
According to the Shatkarma Sangraha there are seven practices of vajroli. The practice involves years of preparation which commences with the simple contraction of the uro-genital muscles and later the sucking up of liquids. Only after the sixth practice is perfected can the seventh be successfully attempted by the yogi.
That is the practice included in maithuna, yogic intercourse. Through this practice of vajroli the sexual energy, hormones and secretions are re-assimilated into the body. Its outcome is the union of the negative and positive poles of energy within one's own body.
By and large, people have inherited a concept that these practices are unnatural or bad. Many commentators on the Hatha Yoga Pradipika avoid discussing these slokas, dismissing them as obscene practices indulged in by low-caste tantrics. Obviously they have an incorrect understanding of the practice. People have concocted the notion that spiritual life is separate from mundane life and the physical body because of past religious conditioning which has become perverted. These people must realise that spiritual life is not anti-sexual and sexual life is not anti-spiritual.
Of course, celibacy has its own rewards, but according to tantra it should arise spontaneously, not out of suppression. Spiritual life means developing awareness by applying the higher mind to the experiences of the body. Whatever we do should be a means to creating yoga in our being. Why should sexual life be excluded? According to this sloka sexual life can be elevated from the sensual to the spiritual plane if it is practised in a particular way, and for this vajroli mudra has been prescribed.
A person who has perfect control of the body and mind is a yogi in every situation. A person who gorges himself on food, for example, is just as 'obscene' as a person who indulges in uncontrollable sexual acts. Sexual life has three purposes, and this should be understood. For the tamasic person, it is progeny; for the rajasic person, it is pleasure; for a sattwic person, it is for enlightenment.
The desire to release semen is an instinctual urge experienced throughout nature, not only by humans. Therefore, there should be no guilt or shame associated with it. Animal consciousness is not the end stage in the evolutionary destiny for a human being. Man's potential for 'bliss' can be extended beyond the momentary experience which accompanies the release of semen. Semen and ova contain the evolutionary potential and if these can be controlled, not only the body but also the mind can be controlled.
Nature has provided the mechanism of seminal release, but although it is generally not known, nature has also provided a means to control this mechanism through various practices of hatha yoga. If the release of semen and ova can be controlled, a new range of experience dawns. Those experiences are also endowed by nature, even if only a few people have gained them. Therefore the techniques should not be considered to be against the natural order.
Although medical science has generally failed to acknowledge the fact, uncontrolled release of semen throughout life does contribute to premature deterioration of the vital capacities of the brain, overburdens the heart and depletes the nervous system. Actually it is a matter of degree and there is no limit to perfection. Many men die prematurely of physical and mental exhaustion with their dreams unfulfilled and their goals unattained. However, if the process of seminal release can be arrested, so that energy and spermatozoa do not escape through the generative organ but are redirected upwards into the higher brain centres, then a greater awakening can take place; a greater vision can be realised, and a greater vital power can be directed towards accomplishment in life.
According to the sloka, if vajroli is well practised, even in an otherwise free lifestyle, that yogi's attainments in life will be greater, and a greater source of vital and mental power becomes available to him. A few great yogis and masters had these experiences and have therefore instructed their disciples in the oli mudras and other hatha yoga techniques.
In mundane life the climax of sexual experience is the one time when the mind becomes completely void of its own accord, and consciousness beyond the body can be glimpsed. However, that experience is so short-lived because the energy is expressed through the lower energy centres. This energy which is normally lost can be used to awaken the dormant power of kundalini in mooladhara. If the sperm can be withheld the energy can be channelized through sushumna nadi and the central nervous system to the dormant areas of the brain and to the sleeping consciousness.
The sex act is the one means to totally concentrate and captivate the mind, but in tantra it should not be the ordinary experience. The experience has to be more than the gross or sensual one. Awareness and control have to be developed. The senses have to be developed. The senses have to be utilised, but only as the means of awakening the higher consciousness, not the animal consciousness, and for this vajroli mudra and various tantric rituals are to be perfected.
Vajroli mudra is an important practice today in kali yuga when man's ability and need to express himself in the material and sensual world is predominating. We have to act in the external world and simultaneously develop inner awareness. The purpose of life should be to attain a deeper and more fulfilling experience beyond the empirical sensory experience alone.
Man has four basic desires known as purushartha or chaturvarga, the first of which is karma or sensual gratification. This needs to be fulfilled to a certain extent but should not pull the consciousness down. It should be a means to accomplish a greater result.
Every action, including the sex act, should be directed towards realising the truth of existence. Then you are living a spiritual life. Spiritual life does not depend on living up to puritanical morality.
If you can follow such puritanical ideals and attain enlightenment, then practise them, but do not condemn others who cannot. The moment you create rigid ideals that the spiritual path has to be 'like this' and cannot be 'like that' you are limiting your own ability to have a total experience.
Spiritual unfoldment is the process of evolution. It can happen slowly through millions of years as the process of nature, or it can be accelerated through the practices of yoga. Vajroli mudra accelerates this rate of evolution. Practise of vajroli regulates the entire sexual system. Testosterone level and sperm production are influenced. Even if the yogi is a householder, he does not lose the semen. Therefore, whether one has sexual interactions or not, vajroli should be practised.