Ali ibn AbuTalib commanded him to ask the Messenger of Allah ﷺ what a man should do when he wants to have intercourse with his wife and the prostatic fluid comes out (at this moment). (He said): I am ashamed of consulting him because of the position of his daughter. Al-Miqdad said: I asked the Messenger of Allah ﷺ about it. He said: When any of you finds, he should wash his private part, and perform ablution as he does for prayer.  

أَنْ يَسْأَلَ لَهُ رَسُولَ اللَّهِ ﷺ عَنِ الرَّجُلِ إِذَا دَنَا مِنْ أَهْلِهِ فَخَرَجَ مِنْهُ الْمَذْىُ مَاذَا عَلَيْهِ فَإِنَّ عِنْدِي ابْنَتَهُ وَأَنَا أَسْتَحْيِي أَنْ أَسْأَلَهُ قَالَ الْمِقْدَادُ فَسَأَلْتُ رَسُولَ اللَّهِ ﷺ عَنْ ذَلِكَ فَقَالَ إِذَا وَجَدَ أَحَدُكُمْ ذَلِكَ فَلْيَنْضَحْ فَرْجَهُ وَلْيَتَوَضَّأْ وُضُوءَهُ لِلصَّلاَةِ  

I was a man who emitted a great deal of madhi, but I felt too shy to ask the Messenger of Allah ﷺ because of his daughter, so I told Al-Miqdad to ask the Messenger of Allah ﷺ about a man who finds madhi. He said: ʿThat is the water of the male, and every male has water, so let him wash his private part and testicles and do wudoo’ as for prayer.ʿ  

أَنْ أَسْأَلَ رَسُولَ اللهِ ﷺ مِنْ أَجْلِ ابْنَتِهِ فَأَمَرْتُ الْمِقْدَادَ فَسَأَلَ رَسُولَ اللهِ ﷺ عَنِ الرَّجُلِ يَجِدُ الْمَذْيَ فَقَالَ ذَلِكَ مَاءُ الْفَحْلِ وَلِكُلِّ فَحْلٍ مَاءٌ فَلْيَغْسِلْ ذَكَرَهُ وَأُنْثَيَيْهِ وَلْيَتَوَضَّأْ وُضُوءَهُ لِلصَّلاةِ  

"I said to Al-Miqdad: 'If a man is intimate with his wife and excretes prostatic fluid but does not have intercourse - ask the Prophet ﷺ about that, for I am too shy to ask him about it since his daughter is married to me.' So he asked him, and he said: 'Let him wash his male member and perform Wudu' as for Salah.'" (Using translation from Nasāʾī 153)  

قُلْتُ لِلْمِقْدَادِ إِذَا دَنَا الرَّجُلُ مِنْ أَهْلِهِ فَأَمْذَى وَلَمْ يُجَامِعْ فَسَلْ لِيَ النَّبِيَّ ﷺ عَنْ ذَلِكَ فَإِنِّي أَسْتَحْيِي أَنْ أَسْأَلَهُ عَنْ ذَلِكَ وَابْنَتُهُ تَحْتِي فَسَأَلَهُ فَقَالَ «يَغْسِلُ مَذَاكِيرَهُ وَيَتَوَضَّأُ وُضُوءَهُ لِلصَّلَاةِ»