أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنِ ابْنِ شِهَابٍ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ عَائِشَةَ، - رضى الله عنها - قَالَتْ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا أَرَادَ أَنْ يَنَامَ وَهُوَ جُنُبٌ تَوَضَّأَ وُضُوءَهُ لِلصَّلاَةِ قَبْلَ أَنْ يَنَامَ ‏.‏

It was narrated that 'Aishah said: "If the Messenger of Allah (PBUH) wanted to sleep while he was Junub, he would perform Wudu' as for prayer before sleeping." Translation Not Available

Book Ref: Sunan An Nisai Book 1 Hadith 259
Web Ref:  Sunan An Nisai Not Available