"Matsya, the third of the Ms, refers to fish. For the physically minded practitioner Shiva applied the same instruction regarding fish as he did with wine and meat. In spiritual or subtle Tantra the "fish" refers to two subtle nerves which run up the body, starting at the base of the spine and crisscrossing each other and ending in the two nostrils. These nerves are known as the w:Nadi (yoga)ida and pingala. By the science of breath control, Pranayama, the currents of the nerves are controlled and the mind becomes calm for meditation. This is the Matsya of the spiritual practitioner."