Kriyā-tantra

…different groups of tantras (the Kriya-tantra, Charya-tantra, Yoga-tantra, and Anuttarayoga-tantra) that are compared with the fourfold phases of courtship (the exchange of glances, a pleasing or encouraging smile, the holding of hands, and consummation in the sexual act). The first stage involves external ritual acts, and the second combines these