Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 62: Śunaḥśepa Saved
Text 1.62.19

पवित्रपाशैरासक्तो रक्तमाल्यानुलेपनः।
वैष्णवं यूपमासाद्य वाग्भिरग्निमुदाहर॥

pavitra-pāśair āsakto rakta-mālyānulepanaḥ
vaiṣṇavaṁ
yūpam āsādya vāgbhir agnim udāhara

pavitra-pāśaiḥ āsaktaḥ = bound by the sacred sacrificial ropes; rakta-mālya-anulepanaḥ = and wearing a red garland and sandalwood paste; vaiṣṇavam yūpam āsādya = when you reach the Vaiṣṇava sacrificial pillar; vāgbhiḥ agnim udāhara = recite two mantras [that I will give you] while facing Agni.

Bound by the sacred sacrificial ropes and wearing a red garland and sandalwood paste, when you reach the Vaiṣṇava sacrificial pillar, recite two mantras [that I will give you] while facing Agni.

The sacred sacrificial ropes would be made of darbha grass and so on. The sacrificial pillar was called Vaiṣṇava because its presiding deity was Viṣṇu as we learn from the Śruti.[1] Viśvāmitra instructed Śunaḥśepa to face Agni and glorify Indra and Upendra with two mantras [that he would give him].1

[1] vaiṣṇavo vai devatā-yūpaḥ.

1 Since those two verses are mantras from the Śruti portion of the Vedas, they are not explicitly revealed in the Rāmāyana which is a Smṛti scripture.