It was narrated from 'Aishah that:
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." (RU)
English reference (RU): Vol. 1, Book 1, Hadith 356 (RU)
Arabic reference (RU): Book 1, Hadith 384 (RU)