Natyashastra
प्रियाप्रसादने कार्यं होमादिकरणेषु च । महीगताभ्यां जानुभ्यामधोमुखमवस्थितम् ॥ २१०॥
In appeasing a beloved woman, in performing sacrificial acts like the homa, one should sit with both knees touching the ground and the face turned downward.
english translation
priyAprasAdane kAryaM homAdikaraNeSu ca । mahIgatAbhyAM jAnubhyAmadhomukhamavasthitam ॥ 210॥
hk transliteration by Sanscript