Agni Purana 171.6

171.6

māsena bhakṣayedetat suracāndrāyaṇaṃ caret /
tryahamuṣṇaṃ pivedāpastyahamuṣṇaṃ payaḥ pivet //

over a month—one should perform this as the gods' cāndrāyaṇa. / For three days one should drink warm water; for three days one should drink warm milk;