The main characteristic of Tantra (spiritual expression) is that it represents mainly vigour. It represents a pactless fight. Where there is no fight there is no sadhana (spiritual practice).
It is impossible to conquer a crude idea and to replace it by a subtle idea without a fight. It is not possible without spiritual practice. Hence, Tantra is not only a fight, it is an all-round fight. It is not only an external or an internal fight, it is simultaneously both.