Valmiki Ramayana Yuddha Kanda Sarga 74 Shloka 49

सः he, भुजङ्गकल्पम् resembling a serpent, पुच्छम् bending his back, उद्यम्य raising, पृष्ठम् tail, विनम्य bent down, श्रवणे ears, निकुञ्च्य bending, बडबामुखाभम् opening widely, वक्त्रम् mouth, विवृत्य expounded, निचण्डवेगः terrible speed, व्योम्नि sky, आपुफ्लुवे sprang up.

Raising his tail which resembled a serpent, bending his back, and ears, opening his mouth wide expounded Hanuman sprang up at terrific speed.