Musannaf Ibn Abi Shayba 3:289

Ibn Idris narrated to us, from ‘Asim ibn Kulayb, from his father, from Wa’il ibn Hujr, who said: I said, "I will surely look at the prayer of the Prophet, may Allah bless him and grant him peace." He said: So he prostrated, and I saw his head between his hands, at the same distance as where he began [the prayer], saying: "Close to his ears."