Matsya Purana — Bhīma-Dvādaśī
योनिवक्त्रं च तत्कृत्वा ब्राह्मणैः यवसर्पिषी तिलांश्च विष्णुदेवत्यैर् मन्त्रैरेकाग्निवत्तदा //
yonivaktraṃ ca tatkṛtvā brāhmaṇaiḥ yavasarpiṣī tilāṃśca viṣṇudevatyair mantrairekāgnivattadā //
Then, having fashioned its mouth in the prescribed yoni-form (yoni-vaktra), one should, together with brāhmaṇas, offer barley with ghee and also sesame—at that time—using mantras addressed to Viṣṇu, performing the rite as in the one-fire (ekāgni) procedure.
This verse is not about pralaya; it focuses on correct ritual performance—specific offerings and Viṣṇu-directed mantras—rather than cosmic dissolution.
It reflects dharma as disciplined ritual observance: a householder (and by extension a king upholding public dharma) performs sanctioned offerings with qualified brāhmaṇas and proper mantras, following the ekāgni procedure.
The significance is ritual-technical: a prescribed ‘yoni-mouth’ form (a specific ritual configuration), offerings of yava with ghee and tilas, and performance ‘as in ekāgni’—i.e., using a single consecrated fire with Viṣṇu-devatya mantras.