Real yoga practice is to control the senses and, after…

““Real yoga practice is to control the senses and, after such control is established, to concentrate the mind on the Nārāyaṇa form of the Supreme Personality of Godhead, Śrī Kṛṣṇa. Lord Kṛṣṇa is the original Personality of Godhead, and all the other Viṣṇu forms – with four hands decorated with conch, lotus, club and wheel – are plenary expansions of Kṛṣṇa. In Bhagavad-gītā it is recommended that one meditate upon the form of the Lord. To practice concentration of the mind, one has to sit with the head and the back in a straight line, and one must practice in a secluded place, sanctified by a sacred atmosphere. The yogī should observe the rules and regulations of brahmacarya – to strictly live a life of self-restraint and celibacy. One cannot practice yoga in a congested city, living a life of extravagancy, including unrestricted sex indulgence and adultery of the tongue. Yoga practice necessitates controlling the senses, and the beginning of sense control is to control the tongue. One who can control the tongue can also have control over the other senses. One cannot allow the tongue to take all kinds of forbidden food and drink and at the same time advance in the practice of yoga. It is a very regrettable fact that many unauthorized so-called yogīs come to the Western countries and exploit people’s inclination towards yoga practice. Such unauthorized yogīs even dare to say publicly that one can indulge in the habit of drinking and at the same time practice meditation.””

— A.C. Bhaktivedanta Swami Prabhupāda