Shiva Purana
आस्तीर्य्य दर्भान्पूर्वाग्रान्भूस्स्वाहा च भुवस्सुवः ॥ प्रणवादि प्रोच्य भूमौ पायसान्नं बलिं हरेत् ॥ ४४ ॥
He shall spread Darbha grass on the ground with their tips to the east. After saying “Bhūḥ Svāhā, Bhuvaḥ Svāhā, Suvaḥ Svāhā, Om.” He shall offer milk pudding as oblation.
english translation
AstIryya darbhAnpUrvAgrAnbhUssvAhA ca bhuvassuvaH ॥ praNavAdi procya bhUmau pAyasAnnaM baliM haret ॥ 44 ॥
hk transliteration by Sanscript