“嘘”、“ ”、“呵”、“吹”、“呼”、“嘻”，此六字也。诀云∶肝若嘘时目睁精，
肺知 气手双擎，心呵顶上连叉手，
肾吹抱取膝头平，脾病呼时须撮口，三焦客热卧嘻咛。
“白虎隐于东方，青龙潜于酉位”，此十二字诀也，云转轮法。闭目静坐，叩齿咽津，
口中默念，将十二字一字一圈，作一圆图如轮转，数至三十六遍止。及至收回，从外旋内，
从大至小，念曰∶青龙潜于酉位，白虎隐于东方，亦三十六遍，复归太极而止，是为一周天
。久则不必用意，自然旋转，真有歇手不得处，随则坎（肾）离（心）交，铅（
属坎）汞（属离）合，二物黄，至黄房（戊己居中，规中是也）。戊己真土也，互相吞
啖，两情留恋，盘旋于祖窍之间，自然复此先天之 ，而成混元真一之精，为大药之根原，作还
丹，之基本也。《玉芝》云∶玄黄若也无交媾，争得阳从坎下飞。乃作丹之大端，修仙之第一义
也。然坎离龙虎交，内交也；乾坤子午交，外交也。内交者，使龙虎归于鼎中（脐下），情性合
于窍内，当用“龙从火里出，虎向水边生”之二诀，始得龙虎交矣。外交者，以精气神归玄牝（
此与祖 共窍），窍中与祖气聚会，三家相见（身心意合则三家相见），合为一体，凝于混沌，
抱一无离，为返本还原之要道，龙虎交而结婴儿者此也。
"Xu" (Hissing), "Si" (Sighing), "He" (Ha), "Chui" (Blowing), "Hu" (Puffing), and "Xi" (Cheering) are these six characters. The mantra states: When the Liver uses "Xu", open the eyes to gather essence; when the Lungs use "Si", raise both hands high above the head; when the Heart uses "He", cross hands and place them on top of the head; when the Kidneys use "Chui", embrace the knees to keep the body level; when the Spleen uses "Hu", purse the lips as if whistling; when the Sanjiao (Triple Burner) has pathogenic heat, lie down and hum "Xi".
"White Tiger hides in the East, Green Dragon潜 (submerges) in the You position" refers to the Twelve-Character Mantra, also known as the Wheel-Turning Method. Close your eyes and sit quietly, click your teeth and swallow saliva, silently reciting in the mouth. Assign each of the twelve characters to one circle, forming a round diagram like a rotating wheel, counting up to thirty-six repetitions. Upon retracting, rotate from the outer circle inward, from large to small, reciting: "Green Dragon submerges in the You position, White Tiger hides in the East," also for thirty-six repetitions, finally returning to Taiji (Supreme Ultimate) to stop. This constitutes one complete cycle (Zhou Tian). With long practice, deliberate intention is no longer needed; rotation occurs naturally, reaching a state where one feels unable to stop. At this point, Kan (Kidney) and Li (Heart) interact; Lead (associated with Kan) and Mercury (associated with Li) combine, producing the Yellow Sprout, arriving at the Yellow Chamber (Wu and Ji occupy the center, which is the Guizhong acupoint). Wu and Ji represent True Earth, mutually swallowing and blending, lingering affectionately, swirling between the Zuoqiao (Ancestral Aperture). Naturally, primordial Qi is restored, forming the Jing (Essence) of Hunyuan Zhenyi, serving as the root of the Great Medicine and the foundation for the Return Elixir. The *Yuzhi* text states: "If Xuanhuang do not couple, how can Yang fly from beneath Kan?" This is the major aspect of alchemy and the primary principle of immortality cultivation. However, the interaction of Kan, Li, Dragon, and Tiger is internal interaction; the interaction of Qian, Kun, Zi, and Wu is external interaction. Internal interaction means causing Dragon and Tiger to return to the Cauldron (below the navel), merging nature and temperament within the aperture. One should employ the two mantras: "Dragon emerges from fire, Tiger arises from water," thereby achieving the interaction of Dragon and Tiger. External interaction involves returning Jing, Qi, and Shen to the Xuanpin (Mysterious Female, here sharing an aperture with Zuoqiao), gathering with Ancestral Qi within the aperture. The Three Families meet (the unity of Body, Mind, and Spirit constitutes the meeting of three families), merging into one entity, condensing into chaos, embracing the One without separation. This is the essential path of returning to the origin, namely the method of forming the Infant through the interaction of Dragon and Tiger.