Sayyiduna Ali (may Allah be pleased with him) said: I used to have a lot of madhi (pre-seminal fluid). Since the daughter of the Prophet (peace and blessings be upon him) was in my marriage, I felt shy to ask the Prophet (peace and blessings be upon him) about this issue myself. So I said to Sayyiduna Miqdad (may Allah be pleased with him) to ask the Prophet (peace and blessings be upon him) about this issue. So he asked about this issue, and the Prophet (peace and blessings be upon him) said: "Such a person should wash his private part and perform wudu."
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 1009
Hadith Gradingحکم دارالسلام:حديث صحيح، ورواية عروة بن الزبير عن على مرسلة، وانظر مابعده