Samarasa is a tantric tradition and a term connoting yogic experimentation with body and mind. It is the final stage of a long process of assimilation in Hindu culture and thought. Samarasa is the union of prajna (the female) and upaya (the male) principles. One who can unite these two principles in oneself can have the highest knowledge, supreme bliss and become free from fetters of birth and death.
In Hindu tradition samarasa is regarded as the equilibrium of Shiva and Shakti. Complete understanding of this leads to non-duality. Samarasa is a tantric tradition, and there are texts which speak about the essential theoretical and practical features of this type of sadhana (propitiation). The basis of tantrism is Advaita (non-dualistic). Shiva represents the pure atma and Shakti is the creative energy of Shiva, which gives birth to the universe and maintains it. This identity is depicted in the form of a divine couple in intimate embrace; both Shiva and Shakti are one. This realization of the all-embracing Shiva and the false duality is perceived as the realization of the tantric path to Advaita.
Shakti is of a triple nature, iccha, jnana, and kriya. According to this system, the world is real and Shakti is the creatrix of the world. She transcends both dualism and non-dualism. Shiva and Shakti are pure awareness. The phenomenal world is nothing but awareness limited by form. Shakti has the veiling and disclosing capacity. She is responsible for multiplication and differentiation, which is the universe. She is the means through which man transcends all multiplicity and recovers the unitary ground of atma.