Śatapatha Brāhmaṇa ("of a hundred paths") 3.7.4.6

3.7.4.6

athopagṛhṇāti | apām perurasīti tadenamantarato medhyaṃ karotyathādhastādupokṣatyāpo devīḥ svadantu svāttaṃ citsaddevahaviriti tadenaṃ sarvato medhyaṃ karoti

With (Vâg. S. VI, 10), 'Thou art a drinker of water,' he then holds (the lustral water) under (its mouth), whereby he renders it internally pure. He then sprinkles it underneath (the body), with, 'May the divine waters make it palatable, a true palatable offering to the gods!' he thus makes it sacrificially pure all over.