Shiva Purana
ततोऽग्नये स्विष्टकृते स्वाहेति जुहुयात्सकृत्॥ हुत्वोपरिष्टात्तन्त्रन्तु ततोऽग्नेरुत्तरे बुधः ॥ ११॥
Then one should offer oblations of Svaha to the fire for the sacrifice. After offering oblations the tantra should be placed on the north side of the fire.
english translation
tato'gnaye sviSTakRte svAheti juhuyAtsakRt॥ hutvopariSTAttantrantu tato'gneruttare budhaH ॥ 11॥
hk transliteration by Sanscript