Whenever the Prophet (ﷺ) went for answering the call of nature, I and another boy used to go after him with a staff, a stick or a short spear (or stick) and a tumbler of water and when he finished from answering the call of nature we would hand that tumbler of water to him.
Sahih al-Bukhari Book 8, Hadith 147
← Previous Hadith that he had heard his father saying, "Allah's Messenger (ﷺ) came to us at midday and water was brought for his ablution. He performed ablution and led us in Zuhr and `Asr prayers with a short stpear (or stick) planted in front of him (as a Sutra), while women and donkeys were passing beyond it."

Sahih al-Bukhari Book 8, Hadith 146 Next Hadith → Allah's Messenger (ﷺ) came out at midday and offered a two-rak`at Zuhr and `Asr prayers at Al-Batha and a short spear (or stick) was planted in front of him (as a Sutra). He performed ablution and the people took the remaining water left after his ablution and rubbed their bodies with it.

Sahih al-Bukhari Book 8, Hadith 148