In the process of sexual intercourse between men and women, when the penis is pulled up to produce strong sexual excitement, the middle finger of the left hand slightly presses the porch point between the two eyebrows on the forehead, and through imagination and visual self-suggestion, all thoughts are focused on this point, which is called guarding the xuan. Inserting the penis into a woman's Kunshi, also known as Kungang, is the place where the posterior fornix of vagina meets the recess of rectum and uterus, and it is a paradise where the legendary immortals live. Then close your mouth, cooperate with your lips, lift your whole body with contracted ribs and abdomen, and exhale slightly. Here is the place where the three flowers of life and wisdom gather at the top of Kunlun Mountain, which leads the essence and blood gas of the internal organs to the source of femininity and masculinity in the human body-the air in nature. There is a poem that sings: Hold the golden seal, ride the ox backwards, and hold the Xuan point with one finger to make the Yellow River flow backwards; The penis churning in the vagina, like a black dragon drinking the sea, climbed the peak of Kunlun Mountain by upside down with fire and water, and swam in the paradise where the gods lived. Another poem sings: put your tongue on the palate, keep your eyes on the top, hold a golden seal in your hand, and hold a golden well in your hand; With the tail pass and the spine pass between them, I slowly took a breath and climbed to the top of Kunlun Mountain where the immortal lived.