The Prophet ﷺ used to pray eleven units of prayer at night, making one of them the witr. When he finished, he would lie down on his right side.
أن النبي ﷺ كان يصلي من الليل إحدى عشرة ركعة، يوتر منها بواحدة، فإذا فرغ اضطجع على شقه الأيمن.
Malik narrated it in Salat al-Layl (8) from Ibn Shihab, from Urwa bin Zubayr, from Ayesha, and he mentioned it. Muslim narrated it in Salat al-Musafirin (736) through the route of Malik, and he mentioned it. He also narrated it through the route of Amr bin Harith, from Ibn Shihab with the same chain, and in it, the Messenger of Allah ﷺ used to pray, between finishing the Isha prayer and Fajr, eleven rakats, giving the salam after every two rakats, and finishing with a single rakat as witr. When the muezzin fell silent after the call for the Fajr prayer, and dawn had become clear to him, and the muezzin came to him, he would rise and pray two light rakats, then lie down on his right side until the muezzin came to him for the iqamah.Bukhari narrated it in Tahajjud (1123) through the route of Shuayb, from Zuhri, and in it he said, he used to pray eleven rakats, that was his prayer. He would remain in the sajdah for as long as it takes one of you to recite fifty verses before raising his head. He would pray two rakats before the Fajr prayer, then lie down on his right side until the caller came to him for the prayer.