) "For his daughter is (married) to me and I feel too shy to ask him." So he asked the Messenger of Allah ﷺ about that and he said: "If any one of you notices that let him sprinkle water on his private parts and perform Wudu' as for prayer."  

أَنْ يَسْأَلَ رَسُولَ اللَّهِ ﷺ عَنِ الرَّجُلِ إِذَا دَنَا مِنَ الْمَرْأَةِ فَخَرَجَ مِنْهُ الْمَذْىُ فَإِنَّ عِنْدِي ابْنَتَهُ وَأَنَا أَسْتَحْيِي أَنْ أَسْأَلَهُ فَسَأَلَ رَسُولَ اللَّهِ ﷺ عَنْ ذَلِكَ فَقَالَ إِذَا وَجَدَ أَحَدُكُمْ ذَلِكَ فَلْيَنْضَحْ فَرْجَهُ وَلْيَتَوَضَّأْ وُضُوءَهُ لِلصَّلاَةِ  

He asked the Prophet about a man who approached his wife, but did not ejaculate. He said: "If anyone of you finds that, he should sprinkle water over his private part (meaning he must wash it) and perform ablution."  

أَنَّهُ سَأَلَ النَّبِيَّ ﷺ عَنِ الرَّجُلِ يَدْنُو مِنِ امْرَأَتِهِ فَلاَ يُنْزِلُ قَالَ إِذَا وَجَدَ أَحَدُكُمْ ذَلِكَ فَلْيَنْضِحْ فَرْجَهُ يَعْنِي لِيَغْسِلْهُ وَيَتَوَضَّأْ  

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. (Using translation from Abū Dāʾūd 207)   

أَنْ يَسْأَلَ رَسُولَ اللَّهِ ﷺ عَنِ الرَّجُلِ إِذَا دَنَا مِنْ أَهْلِهِ مَاذَا عَلَيْهِ؟ فَإِنْ عِنْدِي ابْنَتَهُ وَأَنَا أَسْتَحْيِي أَنْ أَسْأَلَهُ قَالَ الْمِقْدَادُ فَسَأَلْتُ رَسُولَ اللَّهِ ﷺ فَقَالَ «إِذَا وَجَدَ ذَلِكَ فَلْيَنْضَحْ فَرْجَهُ وَلْيَتَوَضَّأْ وُضُوءَهُ لِلصَّلَاةِ»