Shiva Purana
प्रणवं पूर्वमुच्चार्य्य सप्तधा ब्रह्मभि स्ततः ॥ पञ्चभिश्चाभिषेकान्ते शंखोदेनाभिवेष्टयेत् ॥ ३७ ॥
After uttering the Praṇava once first and then seven times with the names of five Brahmans he shall encircle him at the end of the ablution with the water from the conch.
english translation
praNavaM pUrvamuccAryya saptadhA brahmabhi stataH ॥ paJcabhizcAbhiSekAnte zaMkhodenAbhiveSTayet ॥ 37 ॥
hk transliteration by Sanscript