Śatapatha Brāhmaṇa ("of a hundred paths") 4.1.2.22

4.1.2.22

atha hutvāvāñcaṃ grahamavamārṣṭi | idaṃ vā upāṃśuṃ hutvordhvamunmārṣṭyathātrāvāñcamavamārṣṭi pratyañcamevāsminnetadudānaṃ dadhāti

And, having offered, he wipes the cup clean downwards. For even now, after offering the Upâmsu, he wiped (the cup) upwards; but here he wipes it downwards; whereby he puts the in-breathing into him as one tending towards him.