Hadith: When the Messenger of Allah (may Allah's peace and blessings be upon him) entered the privy, a servant and I used to carry a waterskin and a pointed staff, and he would cleanse himself with water

عن أنس بن مالك رضي الله عنه قال: ((كان رسول الله صلى الله عليه وسلم يدخل الخلاء، فأحمل أنا وغلام نَحوِي إِدَاوَةً مِن ماء وَعَنَزَة؛ فيستنجي بالماء)).
[صحيح] - [متفق عليه]

Anas ibn Mālik (may Allah be pleased with him) reported: When the Messenger of Allah (may Allah's peace and blessings be upon him) entered the privy, a servant and I used to carry a waterskin and a pointed staff, and he would cleanse himself with water.
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

Anas ibn Mālik (may Allah be pleased with him), the servant of the Prophet (may Allah's peace and blessings be upon him), mentioned that whenever the Prophet (may Allah's peace and blessings be upon him) would enter the bathroom, Anas, along with another servant, would bring a small waterskin which he used to purify himself with water. They also used to bring something to conceal him from the sight of people, which was a short stick with an iron tip to be fixed in the ground and a garment or the like would be hung over it so as to hide him from the sight of passers by, and also to be used as a Sutrah in case he wanted to pray (i.e. to place it before him so that no one would pass right in front of him while praying).