Valmiki Ramayana Sundara Kanda Sarga 53 Shloka 35
Original Shlokaदृश्यते च महाज्वालः करोति न च मे रुजम्।।5.53.35।। शिशिरस्येव सङ्घातो लाङ्गूलाग्रे प्रतिष्ठितः।
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महाज्वालः huge flame, दृश्यते seeing, मे my, रुजम् न करोति च is not hurting me, लाङ्गूलाग्रे at the end of my tail, शिशिरस्य like the coolness, सङ्घातः like mass of ice, प्रतिष्ठितः इव is placed.
'This huge flame is not hurting me. It is as though a mass of ice is placed at the end of my tail. (The fire did not torture nor extend beyond the tip of my tail.)