Kauthumagrihyasutra 2

Now then, having faced east, having sat down upon darbha grass with points directed to the north loudly pronouncing ‘Om’, he should then have the drawing of the lines performed while looking into the domestic fire.
Having offered that morning oblation, he should obtain a brahmin priest who knows the Veda; in his absence, the rule of the Khādira school [applies]; having [said]: ‘A parasol and an upper garment’, that is the rule of the Khādira school—so say some—he should invite the brahmin priest.
He should say to the brahmin priest: ‘Bhūr bhuvas svar; Bṛhaspati is the Brahmā priest, I am the human one.’ The preceptor should give two blades of darbha grass. The brahmin priest, [reciting:] ‘Parāvasu is cast away’, having cast away a blade of grass to the south, having spread darbha grass with points directed east for a seat, [reciting:] ‘May I sit in the seat of the Vasu’, facing north, should sit down softly uttering ‘Om’. The preceptor, having worshipped the brahmin priest, then having taken a bronze vessel or an unbroken earthen vessel, excluding copper, [or] silver, having taken husked grains of rice with a new winnowing-basket, having moved it to the north, should fill the vessel once for the purpose of the ritual pouring out of sacrificial grain.
It is to be done twice silently. He should say: ‘I sprinkle [it] with Om.’ The waters clarify [it]; having moved it to the north, then, among the procedures of the clarified butter offerings beginning with sweeping up [the sacrificial ground] as stated in the domestic manual, the rite of the new-moon day is to be done; having lifted that vessel and placed it in the middle of the fire, he should say: ‘[This is] the ritual pouring out of sacrificial grain.’ Then he should cook the living grains of rice.
Having basted [it] with the sacrificial ladle, having moved it to the north of the two ends of the grass strewn around the fire, he should perform the consecration by sprinkling again.
Then, taking the sacrificial firewood, a particular rule regarding the kindling stick is stated there:
The Ṛgvedic priests sacrifice with khādira wood, the Baudhāyanas with palāśa, the Sāmavedic chanters with udumbara.
Having caused them to be made a span in length, with edges like a whip’s back, straight-tipped, of the measure of the thumb-joint [or] of the measure of an oblation of clarified butter, with well-marked tips—in their absence, with seventeen [blades] of darbha grass—having taken [them], taking these seventeen: one for the sake of what is not destroyed, one for the sake of the introductory formula, fifteen for the sake of the sacrificial firewood; having basted [them] with the sacrificial ladle, having placed the tip, the middle, and the root to the north for the sake of the after-offerings, having thrown the fifteen into the fire, he should mutter the introductory formula with the remainder; as long as […] ends in śaṭha, so long wearing good garments, having offered the forms into the fire, having worshipped the remaining unhusked grains, then having offered with the three mystic utterances, then having offered the mystic utterance of desire, he should offer the fourfold-taken [clarified butter] into the two eyes [of the fire] with the sacrificial ladle.
Among these, in the ritual procedure for cooked mess, these should be according to purpose; but the specific rule there is stated in the manual on the granting of boons.
And by the rule of the Khādira school, from what is stated in the domestic manual: ‘according to the opinion of Kuthuma’—having said this, the Kauthuma follower follows the path of Kuthuma.

KauthGS 3: