Kaushitakagrihyasutra 3.14.2

3.14.2

brāhmaṇān vedaviduṣo 'yugmān tryavarārdhyān pitṛvadupaveśyāyugmānyudapātrāṇi tilairavakīrya brāhmaṇānāṃ pāṇiṣu ninayet \2\

Having seated an uneven number of Brahmins learned in the Veda, at least three, in the manner of the ancestors, having scattered sesame seeds into an uneven number of water-vessels, he should pour [the water] into the hands of the Brahmins.