Rather than a single coherent system, Tantra is an accumulation of practices and ideas which has among its characteristics the use of ritual, energy work, in some sects transgressional acts, the use of the mundane to access the supramundane and the identification of the microcosm with the macrocosm. The Tantric practitioner seeks to use the divine power that flows through the universe (including their own body) to attain purposeful goals. These goals may be spiritual, material or both.
A practitioner of tantra considers mystical experience or the guidance of a Guru imperative. In the process of working with energy the Tantric has various tools at their disposal. These include yoga ~ to actuate processes that will yoke the practitioner to the divine. Also important are the use of visualizations of the deity and verbalisation or evocation through mantras ~ which may be construed as seeing and singing the power into being; identification and internalisation of the divine is enacted ~ often through a total identification with a deity, such that the aspirant 'becomes' the deity , the Ishta-Devata.
The philosophy of Tantra is revealed in the Agamas or Tantras. Tantras exists in Vaisnava, Shaiva, Ganapatya, and Shakta forms, amongst others.
The Tantric tradition, or Tantrika Parampara, may be considered as either parallel to, or intertwined with, the Vedic tradition (Vaidika Parampara). Swami Nikhilananda wrote not only of the close affinity with the Vedas, but also that the development of Tantric thought shows the influence of the Upanishads, the Puranas and Yoga. Tantra itself speaks of its origins. For example, the Tripura Rahasya, one of the central texts of Shakta Tantra, says, "This text has been created by summarising the teachings of the Vedas, Puranas and other scriptures."
According to Tantra, Reality is pure consciousness (Sanskrit: cit), which is considered to be identical with both being (Sanskrit: sat) and bliss (Sanskrit: ananda).In Tantra, this being-consciousness- bliss or Satchidananda is enshrined as Shiva~Shakti, a conjoined term conveying the inseparable nature of Shiva (the Absolute) and Shakti (the power of creation). In Tantra, any conception of the Divine which does not include Shakti, or the power to become, is considered to be incomplete.
According to Tantra, being-consciousness- bliss or Satchidananda has the power of both self-evolution and self-involution. Reality evolves into a multiplicity of creatures and things, yet at the same time always remains pure consciousness, being and bliss. In this process of evolution, Maya (illusion) conceals Reality and separates it into opposites, such as conscious and unconscious, pleasant and unpleasant, and so forth. These determining conditions if not realised as illusion; bind, limit and fetter (pashu) the individual (jiva).
In this relative dimension, Shiva and Shakti are perceived as separate. However in Tantra, even in the state of evolution, Reality remains pure consciousness, being, and bliss, though Tantra does not deny either the act or fact of this evolution. In fact, Tantra affirms that both the world process itself and the individual jiva are themselves Real. In this, Tantra distinguishes itself from pure dualism as well as from the qualified non-dualism of Vedanta.
However, evolution or the 'outgoing current' is only one half of the functioning of Maya. Involution, or the 'return current', takes the jiva back towards the source or root of Reality, revealing the infinite. Tantra is understood to teach the method of changing the 'outgoing current' into the 'return current', transforming the fetters created by Maya into that which 'releases' or 'liberates'. This view underscores two maxims of Tantra: "One must rise by that by which one falls" and "the very poison that kills becomes the elixir of life when used by the wise."
The Tantric method is to sublimate rather than negate relative reality. This method of sublimation consists of three phases: purification, elevation and the "reaffirmation of identity on the plane of pure consciousness."
Sexual rites may have emerged from early Hindu Tantra as a practical means of generating transformative bodily fluids. These constituted a vital offering to Tantric deities. Sexual rites may also have evolved from clan initiation ceremonies involving the transaction of sexual fluids. Here the male inititate was inseminated or insanguinated with the sexual emissions of the female consort, sometimes admixed with the semen of the guru. He was thus transformed into a son of the clan (kulaputra) through the grace of his consort. The clan fluid (kuladravya) or clan nectar (kulamrita) was conceived as flowing naturally from her womb. Later developments in the rite emphasised the primacy of bliss and divine union, which replaced the more bodily connotations of earlier forms. Although popularly equated with Tantra in its entirety in the West, a minority of sects practised sexual rites. For many practicing lineages, these maithuna practices progressed into psychological symbolism.
When enacted as enjoined by the tantras the ritual culminates in a sublime experience of infinite awareness, by both participants. The Tantric texts specify that sex has three distinct and separate purposes — procreation, pleasure and liberation. Those seeking liberation eschew frictional orgasm for a higher form of ecstasy, as the couple participating in the ritual, lock in a static embrace. Several sexual rituals are recommended and practised. These involve elaborate and meticulous preparatory and purificatory rites. The act balances energies coursing within the pranic ida and pingala channels in the subtle bodies of both participants. The sushumna nadi is awakened and kundalini rises upwards within it. This eventually culminates in samadhi wherein the respective individualities of each of the participants are completely dissolved in the unity of cosmic consciousness. Tantrics understand the act on multiple levels. The male and female participants are conjoined physically and represent Shiva and Shakti, the male and female principles. Beyond the physical, a subtle fusion of Shiva and Shakti energies takes place resulting in a united energy field. On an individual level, each participant experiences a fusion of their own Shiva and Shakti energies.

Have you heard of Vatsyayana?
It is the earliest surviving example of a written love-manual. It was compiled by the Indian sage Vatsyayana sometime in the 1st Century BC. His work was based on earlier Kama Shastras or "Rules of Love" going back to at least the 7th Century BC and is a compendium of the social norms and love-customs of patriarchal Northern India around the time he lived.
Vatsyayana's Kama Sutra is valuable today for his psychological insights into the interactions and scenarios of love and for his structured approach to the many diverse situations he describes. He defines different types of men and women, matching what he terms "equal" unions {samana maithuna} and gives detailed descriptions of many love-postures.
The Kama Sutra was originally written for the wealthy male city-dweller. It is not, and was never intended to be, a lover's guide for the masses, not is it a "Tantric love-manual". About 300 years after the Kama Sutra became popular, some of the love-making positions described in it were re-interpreted in a Tantric way. Since Tantra is an all-encompassing sensual science, love-making positions are relevant to spiritual practice.
Generally, Tantras recommend the use of only a few different love=postures during spiritual sex sessions. Five principle positions, all of which are found in the Kama Sutra, cover what is normally appropriate. These five principle Tantric love-making positions [which have many variations] are: More when you come and see me or you go to my website!
Vatsyayana's Kama Sutra is divided into 7 parts: General Remarke, Amourous Advances, Acquiring a Wife, Duties and Privileges of a Wife, Relations with Other Men's Wives, and a section about Courtesans and Occult Means. The 7th and last part of the Kama Sutra is an appendix to the main work. It includes detailed formulations of substances familiar to Ayurvedic {Indian Indigenous} Medicine, with the emphasis on Virilifics and Aphrodisiacs. Some magical procedures of a type that in later times would be described as Tantric, are also found in the last chapter of the Kama Sutra.
The terminology used by Vatsyayana is context specific. For example, when he uses the word "Yoga", he is referring to sexual intercourse; the word "Tantra", means to him "method", "technique", or "mechanics"; and he uses the word "Yantra" to mean the sexual organ "utilized as an instrument" or to mean "dildo" or "artificial love-device". Lingam specifically refers to the male sex organ and Yoni refers to the female sex organ.

There are many aspects and belief systems within the Tantras.
Kashmiri Tantra utilizes the Kama Sutra and is the origination for the Neo-Tantra Practitioners of the Western Civilizations.
This is just a summary...
Swara Yoga {Science of Breath-Breathing Techniques}
Raja Yoga {Mental Development-Meditati on}
Hatha Yoga {Asanas-Posture Poses}
Ayurvedic Treatments & Diagnosis also can be applyed
Kama Sutra and Ananga Ranga Methodology

Maya MahaDevi