‘Abd Allah b. ‘Umar reported :
‘Umar b. al-Khattab said to the Messenger of Allah ﷺ that he became sexually defiled at night (asking him what he should do). The Messenger of Allah ﷺ said : You should perform ablution and wash your penis and then sleep.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ قَالَ ذَكَرَ عُمَرُ بْنُ الْخَطَّابِ لِرَسُولِ اللَّهِ ﷺ أَنَّهُ تُصِيبُهُ الْجَنَابَةُ مِنَ اللَّيْلِ فَقَالَ لَهُ رَسُولُ اللَّهِ ﷺ " تَوَضَّأْ وَاغْسِلْ ذَكَرَكَ ثُمَّ نَمْ " .