Amr bin Dinar عمرو بن دينار الأثرم الجمحي · The Book on Salat (Prayer)

"I prayed with the Prophet one night. I stood at his left, so Allah's Messenger took me by my head, from behind me, to put me on his right (side)."

"The Prophet ordered that one prostrate on seven bones and that he not gather his hair nor his garment."

Allah's Messenger (S) said: "When one of you prays the two Rak'ah of Fajr then let him lay down on his right (side)."