I used to serve the Prophet ﷺ. Whenever he wanted to bathe, he would say, "Turn your back toward me." So I would turn my back to him and screen him with it.Once, either Hasan or Husayn was brought to him and urinated on his chest. I came to wash it, and he said, "The urine of a girl is washed off, and the urine of a boy is sprinkled with water."
كنت أخدم النبي ﷺ فكان إذا أراد أن يغتسل قال: ولني قفاك، فأوليه قفاي، فأستره به، فأتي بحسن أو حسين فبال على صدره، فجئت أغسله فقال: يغسل من بول الجارية، ويرش من بول الغلام.
Narrated by Abu Dawud (376), and the wording is his, and Nasai (304), and Ibn Majah (526) (613), all of them from Mujahid bin Musa, from Abdul-Rahman bin Mahdi, told to me by Yahya bin Walid, told to me by Muhal bin Khalifa, told to me by Abu Samh, and he mentioned the hadith. The wording is Abu Dawud's, and he also narrated it from Abbas bin Abdul-Azim Anbari coupled with Mujahid bin Musa, with the same chain. Its isnad is hasan.Ibn Hajar said in Talkhis Habir (1/37-38), "Bazzar and Abu Zura said, 'Abu Samh has nothing else besides this, and I do not know his name.' Others said, 'It is said his name was Iyad.' And Bukhari said, 'It is a hasan hadith.'"I say, it is as he said, for Yahya bin Walid Tai, Abu Zara, falls short of being fully reliable. Nasai said of him, "There is no harm in him," and Ibn Hibban mentioned him among the trustworthy narrators. Ibn Khuzayma also graded it sahih (283).