Śatapatha Brāhmaṇa ("of a hundred paths") 1.8.3.7

1.8.3.7

atha juhvā paridhīntsamanakti | yayā devebhyo 'hauṣīdyayā yajñaṃ samatiṣṭhapattayaivaitatparidhīnprīṇāti tasmājjuhvā paridhīntsamanakti

Thereupon (the Adhvaryu) anoints the enclosing-sticks (paridhi) with (the butter attaching to) the guhû. With that (spoon) with which he has made offering to the gods, with which he has concluded the sacrifice, he thus gratifies the enclosing-sticks: this is why he anoints them with the guhû.