that appear and occur with the seal of this ecstasy and emptiness. This application causes a special ecstasy to be ignited, which one should foster." Karmamudrā The practice of inner heat is closely related to the practice of karmamudrā (las kyi phyag rgya, action seal), referring to meditative sexual union which leads to the four blisses and is practiced along with inner heat yoga. In some lists, such as that of Milarepa, it is listed as a separate dharma. In other systems, such as that of Gampopa, it is listed as a subset of inner heat yoga. This is because it is considered necessary to have control over the vital energies (through inner heat yoga) in order to be successful in karmamudrā. There are various classifications of action seal, karmamudrā (action seal) is a regular human sexual consort, while jñānamudrā (wisdom seal) is a deity consort created through the power of one's visualization. In Tibetan Buddhism, it is rare for this practice to be done with an actual person, and most commonly it refers to an imagined consort (which will be a buddhist tantric deity, i.e. a yidam). According to Ulrich Timme Kragh, in the writings of Gampopa, the six dharmas are associated with the second empowerment, while action seal practice is associated with the third empowerment. As such, action seal practice "represents a stage of practice that may be performed after having perfected the yogas of the Six Dharmas." According to Tsongkhapa, both practitioners of physical action seal yoga should be of the highest capacity, have tantric initiations, be learned in tantra and be able to keep the pledges (samaya), be skilled in the practice of the tantric sadhana and be mature in practicing four daily sessions of yoga. They should also be skilled in meditation on emptiness and in the techniques of inducing the four blisses. Tsongkhapa states that if they do not have these qualities, practicing physical sexual yoga is unwise. In this case, one should just practice with a visualized consort. While many of the traditional lists of types of consorts to seek out for joint practice to gain spiritual attainments are written for males and from a male point of view, there are some rare instructions for these sadhanas and for consort choice from the point of view of female practitioners. Gampopa's presentation Kragh provides the following overview of the practice (from a male perspective)