It is called the ecstatic throb
"Spanda: The Yoga of Vibration"
Experiencing the Pulsation of Divine Consciousness
According to the core Tantric philosophy of Spanda, the ‘Vibration’ of Divine Consciousness manifests as the whole universe, including the physical and subtle bodies of every human being. Tantra teaches us that there is a unifying continuity between our physical bodies, the activities of our mind and emotions, and all forms of interior awareness.
All of these are manifestations of the one source; thus, we are all microcosmic pulsations of the whole, expressions in bodily form, within the illusory dimension of time and space, of Universal Consciousness (Parama Śhiva).
According to the primary teaching on Spanda, the 9th century Kashmiri work known as the ‘Teachings on Vibration,’ the supreme vibration (Spanda) unifies and encompasses all that has emerged from it, and continually re-enfolds the manifest totality of all that exists back into the supreme light of consciousness. The very energy (Śhakti) of consciousness flows into condensed expressions of itself in waves of contraction (nimeṣha) that we recognize as the constituents of the world around us, including bodies, feelings, and thoughts. When Śhaktiseeks to again expand (unmeṣha) into its infinite potential, to identify with more expansive levels of awareness of itself through our own intention, we practice yoga.
Spanda is often called sphuratta, the ‘scintillating pulse’ of the Supreme Light which continuously trembles within its own incandescence. This very vibration makes up the totality of all beings. Thus the Universal Spanda blissfully vibrates as all aspects of the Self. Even ‘negative’ feelings and thoughts are part of Spanda; when it contracts (nimeṣha) into the form of negative thoughts and feelings, these are used as a spring-board to move into an expanded (unmeṣha) state, thus completing the dance of life. But the very doctrine of Spanda is based on the fact that contraction-expansion is the pulsation of the divine. We can only discover our true Being as one with the Universal source when we have balanced action between these two. Then the ‘arising’ (udyama) of consciousness comes, in the still point (bindu) when are breath, heart, and mind becomes one pulsation.
Lead inwards, the yogi discovers that the most delicate and powerful tendrils of individuality merge with the infinitely vast vibration (Spanda) of Divine Consciousness. Mantra recitation (especially ‘om namah śhivaya’) and meditation serve as the inner beacon to light the path through the subtler vibrations of inner awareness, leading to the experience of parispanda, which the tradition calls the ‘blissful pulsation of enlightenment.’ It is called the ecstatic throb that stirs the stillness of the Absolute. To attend consciously to this inner pulse is to unfold deeper and deeper experiences of meditative absorption (samāvesha) until the experience of limitation of any kind is forever broken.
In this state, we have become spiritually awake to the illuminating light of consciousness (prakāśha) that dawns as the source of our beings. It is experienced as totally free, ever-expanding, completely new waves of bliss that continually impact the consciousness of the awakened yogin. The ‘recognition’ of Supreme Spanda within the Self, as the Self, uncovers the well-spring of the nectarean consciousness which streams forth in waves of energy. These ‘waves’ are merely the energies that cause the pulsation of consciousness. They are the dynamism, the vimarśha, the ‘self-consciousness’ of inner light divine. This light is the light of all beings. We are all deeply connected as sacred vibrations of one Eternal, blissful, and Absolute Consciousness (Śhiva).
In Tantric Yoga, we do not seek, therefore, to ‘change’ ourselves; rather, through practice we gradually begin to recognize that everything we have sought outside of ourselves--peace, love, contentment, security, etc., vibrates as the heart energy (hṛidayam) of the universe within our own hearts. Yoga simply unveils this reality as your true nature at the moment that the Śhakti (Divine Energy-Consciousness) begins to expand outward once again in the form of your own awakening. It cannot be otherwise. Our awakening is merely this: we recognize our own heart to be one with the central point of Supreme Consciousness, the point from which all things ebb and flow in the bliss-dance of the Universe.