Vaishnava Dharmashastra 73.25

73.25

bhuktavatsu brāhmaṇeṣu tṛptim āgateṣu, mā me kṣeṣthety annaṃ satṛṇam abhyukṣyānnavikiram ucchiṣṭāgrataḥ kṛtvā, tṛptā bhavantaḥ saṃpannam iti ca pṛṣṭvā udaṅmukheṣv ācamanam ādau dattvā, tataḥ prāṅmukheṣu dattvā, tataś ca suprokṣitam iti śrāddhadeśaṃ saṃprokṣya, darbhapāṇiḥ sarvaṃ kuryāt ||

The Brâhmanas having eaten and being satisfied, let him sprinkle the food (as much as has been left by them) and the grass with the Mantra, 'Mayest thou not fail me,' and strew the food near the leavings; and having asked them, 'Are you satisfied? Is (the Srâddha) finished,' he must first give water for sipping to the Brâhmanas facing the north, and then to those facing the east; and he must sprinkle the place where the Srâddha has been offered (with water, with the Mantra), 'Well sprinkled.' All these rites he must perform while holding blades of sacred grass in his hand.