It wasnarrated that 'Aishah said:
"When the Prophet (ﷺ) prayed thetwo (Sunnah) Rak'ah of Fajr, he would lie down on his right side." (IT)
English reference (IT): Vol. 1, Book 5, Hadith 1198 (IT)
Arabic reference (IT): Book 5, Hadith 1254 (IT)