Śatapatha Brāhmaṇa ("of a hundred paths") 3.8.2.18

3.8.2.18

tām parivāsayati | tām paśuśrapaṇe pratapati tatho hāsyātrāpi śṛtā bhavati punarulmukamagnīdādatte te jaghanena cātvālaṃ yanti ta āyantyāgacantyāhavanīyaṃ sa etattṛṇamadhvaryurāhavanīye prāsyati vāyo vai stokānāmiti stokānāṃ haiṣā samit

He cuts it (the omentum) off on all sides (from the belly) and heats it at the cooking-fire: thus it becomes cooked for him already at this (fire). The Agnîdh again takes a firebrand (from the Sâmitra, and walks in front). They go behind the pit (kâtvâla) and proceed to the Âhavanîya. The Adhvaryu throws that (top part of the) grass-stalk into the Âhavanîya with, 'O Vâyu, graciously accept the drops!' for this is the kindler (samidh) of the drops.