Sahih Muslim Book 003, Hadith Number 0593.
Chapter : On al-Madhi.
'Ali reported: I was one whose prostatic fluid flowed readily and I was ashamed to ask the Apostle (may peace be upon him) about it, because of the position of his daughter. I, therefore, asked Miqdad.b. al-Asad and he inquired of him (the Holy Prophet). He (the Holy Prophet) said: He should wash his male organ and perform ablution.