You might wonder what is meant by ‘secret mantra’. It does not mean the visualization of deities, or the recitation of mantra or the ritual practices for pacifying siddhis, enriching siddhis, magnetizing siddhis and subjugating siddhis. These are not what we call ‘secret mantra’. Nor is it the yogic practice of //tsa-lung// meditation.
Secret mantra is not simply offering tormas, playing Dharma instruments like the //gyaling//, beating drums and doing elaborate Buddhist rituals. If this were the definition of tantra, then it would follow that even Milarepa was not a tantric practitioner. He lived in a cave and had no possessions, he did not even have a bell and vajra, yet he was without question one of the greatest tantric yogis who ever lived.
In mantrayana practice, there must be an understanding of emptiness endowed with compassion, which then transforms into a deity. We then practice identifying with that deity. That is the ‘vajra’ element of vajra-yana. The real practice of secret mantra vajrayana involves generating a mind of emptiness with the heart of compassion (//tong nyi nyingje’i nyingpo chen//) and then transforming that very mind into the pure perception of the deity and feeling a sense of divine pride or confidence.