Sahih al-Bukhari 132
Sahih al-Bukhari · Book 3: Knowledge · Whosoever felt shy (to ask something) and then requested another person to ask on his behalf
Narrated `Ali:
حَدَّثَنَا مُسَدَّدٌ ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دَاوُدَ ، عَنِ الأَعْمَشِ ، عَنْ مُنْذِرٍ الثَّوْرِيِّ ، عَنْ مُحَمَّدٍ ابْنِ الْحَنَفِيَّةِ ، عَنْ عَلِيٍّ ، قَالَ كُنْتُ رَجُلاً مَذَّاءً فَأَمَرْتُ الْمِقْدَادَ أَنْ يَسْأَلَ النَّبِيَّ صلى الله عليه وسلم فَسَأَلَهُ فَقَالَ " فِيهِ الْوُضُوءُ " .
I used to get the emotional urethral discharge frequently so I requested Al-Miqdad to ask the Prophet (ﷺ) about it. Al-Miqdad asked him and he replied, "One has to perform ablution (after it)." (See Hadith No. 269).