The Prophet used to wash his private parts three times. Ibn 'Umar said: "We did that and we found it to be healing and a means of purification."
Sunan Ibn Majah Book 1, Hadith 90
← Previous Hadith "Abu Ayyub Al-Ansari, Jabir bin 'Abdullah, and Anas bin Malik told me that when this Verse: "In it (the mosque) are men who love to clean and to purify themselves. And Allah loves those who make themselves clean and pure." was revealed, the Messenger of Allah said: 'O Ansar! Allah has praised you for your cleanliness. What is the nature of your cleanliness?' They said: 'We perform ablution for prayer and we take bath to cleanse ourselves of impurity due to sexual activity, and we clean ourselves with water (after urinating). He said: 'This is what it is. So adhere to it.'"

Sunan Ibn Majah Book 1, Hadith 89 Next Hadith → "The Messenger of Allah said: 'The (following) was revealed about the people of Quba': 'In it (the mosque) are men who love to clean and purify themselves. And Allah loves those who make themselves clean and pure.'" He said: 'They used to clean themselves with water (after urinating), and this Verse was revealed concerning them.'"

Sunan Ibn Majah Book 1, Hadith 91