Narrated Anas bin Malik: Whenever Allah's Apostle went to answer the call of nature, I along with another boy used to carry a tumbler full of water (for cleaning the private parts) and a short spear (or stick).
Hadith ReferenceSahih Bukhari / The Book of Wudu (Ablution) / Hadith: 152
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة