। ॥ ७७ ॥
In plain words
O Śivā, the faint line on your slender waist, shaped like the finest ripple of Kālindī—the Yamunā—appears, O Mother, to the discerning as ether pressed thin between your pitcher-like breasts and slipping down into the cavern of your navel.
Close to the Sanskrit
That which — this, having the form of a very slender wave of the Kālindī, O Śivā, which shines a little on your thin waist, O Mother, to those of good intellect — [is] as if the ether, having gone into the space between your two pitcher-breasts and become thin from their mutual pressing, were entering your cavernous navel.