Sunan al-Nasa'i The Book of Purification Abdullah bin Mubarak عبد الله بن المبارك Abdur Rahman bin Harmaz al-A'araj عبد الرحمن بن هرمز الأعرج أبو داود Na'm bin Ajyl ناعم بن أجيل Swyd bin Nsr bin Swyd سويد بن نصر بن سويد “I met a man who accompanied the Prophet (ﷺ) as Abu Hurairah (may Allah be pleased with him), accompanied him for four years. He said: ‘The Messenger of Allah (ﷺ) forbade any one of us to comb his hair each day, or to urinate in the place where he performs Ghusl, or for a man to perform Ghusl using the leftover water of a women, or a woman to perform Ghusl using the leftover water of a man – they should scoop it out together.'” It is said this is to prevent him from making his physical appearance his main aim. https://parallelquran.com/hadith/sunan-al-nasai-239/