"I asked Ibn 'Abbas: 'How did the Messenger of Allah ﷺ pray at night?' He said: 'He prayed eleven Rak'ahs including Witr, then he slept deeply until I could hear him snoring, then Bilal came to him and said: "The prayer, O Messenger of Allah!" Then he got up and prayed two brief Rak'ahs then led the people in prayer, and he did not perform Wudu'.'" (Using translation from Nasāʾī 686)  

أَخْبَرَهُ قَالَ سَأَلْتُ ابْنَ عَبَّاسٍ قُلْتُ كَيْفَ كَانَتْ صَلَاةُ رَسُولِ اللهِ ﷺ بِاللَّيْلِ؟ فَوَصَفَ أَنَّهُ «صَلَّى إِحْدَى عَشْرَةَ رَكْعَةً بِالْوِتْرِ ثُمَّ نَامَ حَتَّى اسْتَثْقَلَ فَرَأَيْتُهُ يَنْفُخُ» فَأَتَاهُ بِلَالٌ فَقَالَ الصَّلَاةَ يَا رَسُولَ اللهِ «فَقَامَ فَصَلَّى رَكْعَتَيْنِ وَصَلَّى لِلنَّاسِ وَلَمْ يَتَوَضَّأْ»