Chapter: It is permissible for one who is junub to sleep, but it is recommended for him to perform wudu’, and wash his private parts if
he wants to eat, drink, sleep, or have intercourse
باب جَوَازِ نَوْمِ الْجُنُبِ وَاسْتِحْبَابِ الْوُضُوءِ لَهُ وَغَسْلِ الْفَرْجِ إِذَا أَرَادَ أَنْ يَأْكُلَ أَوْ يَشْرَبَ أَوْ يَنَامَ أَوْ يُجَامِعَل
Anas reported:
The Messenger of Allah (ﷺ) used to have sexual intercourse with his wives with a single bath.
وَحَدَّثَنَا الْحَسَنُ بْنُ أَحْمَدَ بْنِ أَبِي شُعَيْبٍ الْحَرَّانِيُّ، حَدَّثَنَا مِسْكِينٌ، - يَعْنِي ابْنَ بُكَيْرٍ الْحَذَّاءَ - عَنْ شُعْبَةَ، عَنْ هِشَامِ بْنِ زَيْدٍ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَطُوفُ عَلَى نِسَائِهِ بِغُسْلٍ وَاحِدٍ .
Reference : Sahih Muslim 309
In-book reference : Book 3, Hadith 30
USC-MSA web (English) reference : Book 3, Hadith 606
(deprecated numbering scheme)
http://sunnah.com/muslim/3/30