Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 31
Sanskrit:
कं धास्यति कुमारोऽयं स्तन्ये रोरूयते भृशम् ।मां धाता वत्स मा रोदीरितीन्द्रो देशिनीमदात् ॥ ३१ ॥
ITRANS:
kaṁ dhāsyati kumāro ’yaṁstanye rorūyate bhṛśammāṁ dhātā vatsa mā rodīritīndro deśinīm adāt
Translation:
The baby cried so much for breast milk that all the brāhmaṇas were very unhappy. “Who will take care of this baby?” they said. Then Indra, who was worshiped in that yajña, came and solaced the baby. “Do not cry,” Indra said. Then Indra put his index finger in the baby’s mouth and said, “You may drink me.”