Natyashastra
करिहस्तं कटिच्छिन्नं कर्तव्यमपराजिते । कुट्टितं करणं कृत्वा भुजङ्गत्रासितं तथा ॥ १९२॥
The waist should be cut off at the level of the elephant's trunk, and the Bhujangatrāsita mudra should be performed.
english translation
karihastaM kaTicchinnaM kartavyamaparAjite । kuTTitaM karaNaM kRtvA bhujaGgatrAsitaM tathA ॥ 192॥
hk transliteration by Sanscript