Abu Samh said:
"I used to serve the Prophet, and when he wanted to take a bath he would say: 'Turn your back to me.' So I would turn my back and hung up a cloth, and concealed him with it." (ID)
English reference (ID): Vol. 1, Book 1, Hadith 613 (ID)
Arabic reference (ID): Book 1, Hadith 656 (ID)