Shatapatha Brahmana 9.3.2.2

9.3.2.2

yadvevaitāṃ vasordhārāṃ juhoti | abhiṣeka evāsyaiṣa etadvā enaṃ devāḥ sarvaṃ kṛtsnaṃ saṃskṛtyāthainametaiḥ kāmairabhyaṣiñcannetayā vasordhārayā tathaivainamayametatsarvaṃ kṛtsnaṃ saṃskṛtyāthainametaiḥ kāmairabhiṣiñcatyetayā vasordhārayājyena pañcagṛhītenaudumbaryā srucā tasyokto bandhuḥ

And, again, as to why he offers the 'Vasor dhârâ;'--this is his (Agni's) Abhisheka; for the gods, having now completed him wholly and entirely, showered upon him those wishes (or, objects of desire), this 'Vasor dhârâ;' and in like manner does this (Sacrificer), now that he has completed him wholly and entirely, shower upon him those wishes, this 'Vasor dhârâ.' With ghee taken in five ladlings, and an offering-ladle of udumbara wood (he offers): the significance of this has been explained.