Śivasaṃhitā 4.95

The verse’s taxonomy establishes the hierarchical relationship between the three techniques: Vajrolī is the trunk (mūla) from which Sahajolī and Amarolī derive as branches. They are not completely independent practices but modulations of the same fundamental principle — the control of bindu through the urogenital channel — adapted to specific practice contexts.

Bhedato — ‘from difference, by means of difference’ — uses the ablative of bheda (distinction, separation, from the root bhid-, to divide, to separate). The distinction between the three practices is one of degree and moment of application, not of nature: Vajrolī is control before excitement, Sahajolī is control at the moment of imminence, Amarolī is recovery after emission. Together they cover the complete spectrum of situations.

The prescription prayatnena ca sevyate — ‘it should be served, practiced with effort’ — uses the verb sev- (to serve, to attend, to frequent), which in the yoga context describes the relationship of assiduous attention the practitioner maintains with their technique. One does not ‘do’ Vajrolī as one ‘does’ a physical exercise; one ‘serves’ it as one serves a teacher or a deity: with constancy, reverence, and total availability.