Baraa Radiyallahu 'Anhu reports:
"When Rasulullah Sallallahu 'Alayhi Wasallam retired, he put his right hand under his right cheek, and recited this du'aa: Rabbi qini adhaa-baka yauma tub-a-thu 'ibaadaka.Translation... O Allah, save me from Your punishment on the day of qiyaamah". (IT)
English reference (IT): Book 38, Hadith 242 (IT)
Arabic reference (IT): Book 39, Hadith 254 (IT)