The Chod is a distinctive Mahayana Buddhist practice that comprises a visualization of serving up one's body as an offering to all beings. The notion of self-sacrifice is certainly not unique to Buddhism; it is also the metaphor for Christian sacrifice.
With a loving mind, cherish more than a child
The hostile gods and demons of apparent existence,
And tenderly surround yourself with them.
Nourish them always with warm flesh and blood.
With the hook of love and compassion,
Befriend them and never dismiss them.
If, with pure noble thought and enlightened resolve,
You connect them to the sacred Dharma
And they are freed and established in happiness,
Then you, child, whoever you are,
Will be my inseparable friend. ~ Machig Labdron (trans. Sarah Harding, 207.)
Chod by definition is "to cut through". The essence of chod is the prajnaparamita: the pervasive permanent unalterable absolute nature of emptiness. Emptiness is not nothingness, it is the full resplendent quality of subtle appearance and is called unstoppable clarity: the inner capacity of the nature of emptiness. What must be understood about the cutting Chod, is what is to be cut and how it is that we cut it. The answer to what must be cut is the root of samsara. Samsara is the cycles of endless suffering of forever becoming: we must look at what causes that and that cause must be cut.
For us, non-realization of our absolute nature is not because we once realized our nature and then forgot it. It isn't that we had it and then lost it. The essential primary nature of absolute purity is innate in our being. Non-actualized purity is ignorance and so ignorance must be cut. It must be destroyed. It must be liberated.
Next to ignorance of Nature, the poison of desire must be cut. We have basic self-centered recognitions which function as our "I" or "me" or any manner of self-perceptions. Beyond this comes the recognition of everything which isn't "me", generally named "other". through this process of "I" and everything else that is not "I" a dualistic mode begins to function between the two. From this dualism arises the judgment of "it's so pretty" and the subtle attachment of "yes, I like it" which gives way to the gross attachment of "I need it" which is where suffering begins. If we need it and we can't get it, then we suffer: if we need it and we get it and we find out that we didn't want it, then we also suffer. If we need it and we get it and it fades away and dissolves into nothingness as all temporary things will, we suffer... .
Desire is also a stepping stone to hatred which is aversion or the other side of desire. Because I want something, then I have some vested interest in that particular phenomena happening: something comes along such as rain, for example, and blocks the fulfillment and "I don't like that." It's because I had some invested interest in what I wanted that aversion developed. Whatever prevents me from getting what I want results in this same aversion and so we find that at the forefront of aversion is desire.
From the poisons of ignorance, desire, and aversion the mind further complicates its delusion with a very beguiling pride of its own confusion and from this arises jealousy. These complete the full array of the poisons of the mind. In Chod, there is always what are called the four demons or the four maras which are the four obstructing influences.
The first obstruction is the personal defilements of mind: the defilements are the five poisons: ignorance, desire, aversion, pride and jealousy. The second demonic influence is the obstruction of false contentment which is somewhat like pride. One takes for granted good situations thinking that they will go on forever: this is a very big obstacle because it wastes opportunities. The third demonic influence that obstructs the realization of enlightenment is based on self-holding and other-holding. The mind zig zags back and forth from "I like this" and "I don't like that" "this is pretty, that is not" "I need this" "I don't need that". Our mind enticed by the appearance of objects goes to the object and becomes dynamically involved there, totally seduced by samsaric appearances. The fourth obstruction is the root of the other three obstructions, the self-centeredness of one's "I".
The method to cut through these demonic influences is called Chod. One's pure motivation is the blade that cuts though the faults of self-centeredness.
Chod is the practice of generosity with one's most valuable possession, the body. There is nothing we value more, so this is what we use as our gift. Our mind is deathless, our body is not, so we transfer our mind out of our body and pure mind stands complete in space. The body, like a shell, is an empty remain.[sic] Through mantra and visualization, the practitioner transforms the body into a vast and wholesome offering of whatever would be satisfying. The offering is not just substance, but it is also wisdom nectar which fills the vastness of space. This is then offered to all of the Buddhas and Bodhisattvas, to any and all wisdom beings beyond the limit of our understanding. Further it is offered to every sentient being whoever they are, wherever they are. Whatever their particular need is is completely met by this offering and they're completely satisfied and fulfilled immediately and ultimately.
This trains the mind to cut through attachment. By this practice, one accomplishes both the accumulation of merit through generosity and the accumulation of wisdom through understanding the basis of non-reality of our physical form. One understands the nature of emptiness that pervades all beings and this accumulates wisdom. Enlightenment is produced by the two accumulations of merit and wisdom, so this is a path capable of rendering full realization of enlightenment." —Khandro Net