As for the external yoga, the capacity tantra, briefly, it is generally set forth as external with reference to its view and conduct. Regarding its view, oneself and the Buddha are not regarded as equal on the relative level. Regarding its conduct, there is no practise of the yogic discipline of equality. As for the sense of capacity, this refers to the inability to practise the samayas which are not to be observed, and [this practise] is thus not free from the ordinary vows. The internal tantra of skillful means is the opposite of that. One regards oneself as the unmistaken Maheśvara and practises the yogic discipline of equality. Even though nothing is prohibited with regard to the conduct of the three doors, one is unstained by faults and therefore skilled in method.

-- Rongzom Chökyi Zangpo