Sang Puja, also called Mountain of Smoke Puja, is a ritual that involves reciting prayers and the making of a large smoke offering by burning food (oatmeal, beans, cookies, candies, rice, sugar), drinks (wine, juice, milk), pieces of colorful cloth, flowers, medicinal herbs, and incense.
In this kind of Smoke Puja, the smoke or its essence is being offered to four (4) groups of beings: Buddhas, Bodhisattvas, and all the other deities; the dharma protectors; all sentient beings; the nagas and spirits to whom we may owe a karmic debt. For the first two groups, the Smoke is presented as offerings while for the other two, it is given as gifts. In offering these precious substances to the enlightened beings, we gain merits while Dharma Protectors offer us protection and wealth.
It is said that sentient beings take in the offerings by inhaling the Smoke. Beings in the hot hells feel cool and are contended. Similarly, beings in cold hells feel warm and are satisfied. Pretas or hungry ghosts are also happy to experience relief from their unquenchable thirst and hunger. Humans are also satisfied because their aspirations are granted.
Through our numerous past lives, it is a certainty that one must have at one time or another caused harm to the nagas, spirits, local deities, earthly gods and other beings - either intentionally or unintentionally. Perhaps, we climbed a mountain or bathed in a river and destroyed their homes in the process. Because of our harmful actions, we have formed a karmic debt between these beings and ourselves. As a result of this karmic debt, they bring sickness, obstacles and other obscurations upon us to make us "pay" for our harmful actions. In doing a Sang Puja, we are paying off all our karmic debts so that these beings will stop harming us.
Before throwing our plate or cup of offering into the fire, one must not think that the offering is just a plate of food or a cup of drink. Instead, one must visualize that the offering is a vast ocean of precious substances offered to the four beings mentioned above and that all of them are extremely pleased when they receive our offerings and gifts.