Bhashya
भोक्ष्यमाणस्य भुक्तवतश्च यदाचमनं शुद्धयर्थं विज्ञातम्,तस्मिन् प्राणस्य वास इति दर्शनमात्रमिह विधीयते—अद्भिःकृत्वा तपोरूपं सत्यवचनं ब्रह्मचर्यमित्यादिधर्मवान्भूत्वेत्यर्थः ।न पुनर्दैक्षमेव कर्मजातं सर्वमुपादत्ते, अतद्विकारत्वान्मन्थाख्यस्य कर्मणः ।'उपसद्व्रती' इति श्रुत्यन्तरात् पयोमात्रभक्षणं च शुद्धिकारणं तप उपादत्ते ।पौर्णमास्यां रात्रौ कर्म आरभते—सर्वौषधस्य ग्राम्यारण्यानामोषधीनां यावच्छक्यमल्पमल्पमुपादाय तद्वितुषीकृत्य आममेव पिष्टं दधिमधुनोरौदुम्बरे कंसाकारे चमसाकारे वा पात्रे श्रुत्यन्तरात्प्रक्षिप्य उपमथ्य अग्रतः स्थापयित्वा ज्येष्ठाय श्रेष्ठाय स्वाहेत्यग्नावाववसथ्ये आज्यस्य आवापस्थाने हुत्वा स्रुवसंलग्नं मन्थे संपातमवनयेत् संस्रवमधः पातयेत् ॥
In plain words
The water sipped by one about to eat or after eating serves as purification and is here prescribed as the garment of Prana, combined with vows of truth and celibacy. This does not require all elaborate Vedic rituals, but rather the milk-only diet supported by scripture. On the night of the full moon, the rite begins: gathering available village and forest herbs, husking them raw into flour, mixing them with curds and honey in an udumbara bowl shaped like a goblet or spoon, churning them, placing them forward, and offering into the domestic fire with the mantra 'To the eldest, to the best, svaha', while pouring the ladle's remaining drops into the mixture and letting the runoff fall below.
Close to the Sanskrit
Of one about to eat and of one who has eaten, which sipping for purification is known, in that the garment of Prana is mere viewing is enjoined here—having done so, being endowed with duties such as truthfulness as the form of austerity, meaning. Not again does he take up all sacrificial action, due to the churning action not being a modification of that. From another Vedic text 'observing the upasad vow', he takes up austerity consisting of eating only milk as the cause of purification. On the full moon night he begins the action—taking as much as possible of all herbs, village and forest ones, having husked them, raw indeed the ground flour, with curds and honey in an udumbara vessel shaped like a goblet or a spoon, from another Vedic text, having thrown them in, having churned, having placed them in front, to the eldest, to the best, svaha, having offered in the domestic fire in the place of pouring of clarified butter, he should pour the residue adhering to the sruva into the churned mixture, he should drop the runoff below.