I met a man who had accompanied the Prophet ﷺ for four years, just as Abu Hurairah had accompanied him. He said, "The Messenger of Allah ﷺ forbade that any of us should comb his hair every day, or urinate in the place where he bathes, or that a man should bathe with the leftover water of a woman, or a woman with the leftover water of a man. Rather, let them both scoop from the water together."
أخبرنا قتيبة قال حدثنا أبو عوانة عن داود الأودي
لقيت رجلا صحب النبي ﷺ كما صحبه أبو هريرة رضي الله عنه أربع سنين قال نهى رسول الله ﷺ أن يمتشط أحدنا كل يوم أو يبول في مغتسله أو يغتسل الرجل بفضل المرأة والمرأة بفضل الرجل وليغترفا جميعا
Its isnad is sahih. Abu Dawud narrated it in the Book of Purification, chapter on the prohibition against that, hadith 81, from the hadith of Abu Awana, in the same manner, and it is also found in al-Kubra, hadith 240. Ibn Hajar graded it sahih in Bulugh Maram.