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
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا حَفْصُ بْنُ غِيَاثٍ، ح وَحَدَّثَنَا أَبُو كُرَيْبٍ، أَخْبَرَنَا ابْنُ أَبِي زَائِدَةَ، ح وَحَدَّثَنِي عَمْرٌو النَّاقِدُ، وَابْنُ، نُمَيْرٍ قَالاَ حَدَّثَنَا مَرْوَانُ بْنُ مُعَاوِيَةَ الْفَزَارِيُّ، كُلُّهُمْ عَنْ عَاصِمٍ، عَنْ أَبِي الْمُتَوَكِّلِ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا أَتَى أَحَدُكُمْ أَهْلَهُ ثُمَّ أَرَادَ أَنْ يَعُودَ فَلْيَتَوَضَّأْ " . زَادَ أَبُو بَكْرٍ فِي حَدِيثِهِ بَيْنَهُمَا وُضُوءًا وَقَالَ ثُمَّ أَرَادَ أَنْ يُعَاوِدَ .
Abu Sa'id al-Khudri reported: The Messenger of Allah (ﷺ) said: When anyone amongst you has sexual intercourse with his wife and then he intends to repeat it, he should perform ablution. In the hadith transmitted by Abu Bakr. (the words are):" Between the two (acts) there should be an ablution," or he (the narrator) said:" Then he intended that it should be repeated."