It was narrated that 'Ali said:
"I felt too shy to ask the Messenger of Allah (ﷺ) about prostatic fluid because of Fatimah, so I told Al-Miqdad bin Al-Aswad to ask about it, and he (the Prophet (ﷺ)) said: 'Perform Wudu' for that.'" (ES)
English reference (ES): Vol. 1, Book 1, Hadith 157 (ES)
Arabic reference (ES): Book 1, Hadith 158 (ES)