Urwah bin al-Zubayr said: Marwan bin al-Hakam, during his governorship of Madinah, mentioned that ablution is to be performed after touching the penis when a man reaches it with his hand. I rejected that and said: There is no ablution for touching it. Marwan said: Busrah bint Safwan (may Allah be pleased with her) told me that she heard the Messenger of Allah (peace and blessings be upon him) mentioning the things that require ablution, and the Messenger of Allah (peace and blessings be upon him) said: "Ablution is to be performed after touching the penis." Urwah said: I kept going back to Marwan about this until he called a man from his guards and sent him to Busrah bint Safwan, and he asked her about what she had narrated concerning it. Busrah sent back the same as what Marwan had told me from her.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20862