It was narrated that Marwan bin Al-Hakam said that one should perform Wudu after touching one’s penis. Marwan said: “Busrah bint Safwan told me that.” ‘Urwah sent someone to check that, and she said: “The Messenger of Allah صلی اللہ علیہ وآلہ وسلم mentioned what Wudil’ is done for, and said: ‘Touching the penis.”(Sahih)