Musnad Ahmad 606
It was narrated that `Ali(رضي الله عنه)  said:
I was a man who emitted a great deal of madhi, but I felt too shy to ask the Prophet (ﷺ) about that because of the position of his daughter, so I told al-Miqdad bin al-Aswad to ask him, and he said: `Let him wash his private part and do wudoo’.`
حَدَّثَنَا عَبْد اللَّهِ، حَدَّثَنِي مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، حَدَّثَنَا وَكِيعٌ، حَدَّثَنَا الْأَعْمَشُ، عَنِ الْمُنْذِرِ، عَنْ مُحَمَّدِ بْنِ عَلِيٍّ، عَنْ عَلِيٍّ، رَضِيَ اللَّهُ عَنْهُ قَالَ كُنْتُ رَجُلًا مَذَّاءً فَكُنْتُ أَسْتَحِي أَنْ أَسْأَلَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لِمَكَانِ ابْنَتِهِ فَأَمَرْتُ الْمِقْدَادَ فَسَأَلَهُ فَقَالَ يَغْسِلُ ذَكَرَهُ وَيَتَوَضَّأُ‏.‏