Whenever Messenger of Allah ﷺ 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).  

كَانَ رَسُولُ اللَّهِ ﷺ يَدْخُلُ الْخَلاَءَ فَأَحْمِلُ أَنَا وَغُلاَمٌ إِدَاوَةً مِنْ مَاءٍ وَعَنَزَةً يَسْتَنْجِي بِالْمَاءِ  

"When the Messenger of Allah ﷺ would go to the toilet, I and another boy like me would bring a small leather vessel of water and he would clean himself with water."  

سَمِعْتُ أَنَسَ بْنَ مَالِكٍ يَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ إِذَا دَخَلَ الْخَلاَءَ أَحْمِلُ أَنَا وَغُلاَمٌ مَعِي نَحْوِي إِدَاوَةً مِنْ مَاءٍ فَيَسْتَنْجِي بِالْمَاءِ  

When the Messenger of Allah ﷺ entered the privy, a servant and I used to carry a skin of water, and a pointed staff, and he would cleanse himself with water. (Using translation from Muslim 271a)  

أَنَّهُ سَمِعَ أَنَسَ بْنَ مَالِكٍ يَقُولُ كَانَ رَسُولُ اللهِ ﷺ يَدْخُلُالْخَلَاءَ فَأَحْمِلُ أَنَا وَغُلَامٌ نَحْوِي إِدَاوَةً مِنْ مَاءٍ وَعَنَزَةً فَيَسْتَنْجِي بِالْمَاءِ  

"When the Messenger of Allah ﷺ would go to the toilet, I and another boy like me would bring a small leather vessel of water and he would clean himself with water." (Using translation from Nasāʾī 45)  

سَمِعْتُ أَنَسَ بْنَ مَالِكٍ يَقُولُ كَانَ رَسُولُ اللهِ ﷺ «إِذَا دَخَلَ الْخَلَاءَ أَحْمِلُ أَنَا وَغُلَامٌ مَعِي نَحْوِي إِدَاوَةً مِنْ مَاءٍ فَيَسْتَنْجِي بِالْمَاءِ»  

"عَنْ أنَسٍ قَالَ: كَانَ رَسُولُ اللهِ ﷺ دْخُلُ الخَلاَءَ فَأحْمِلُ أَنَا وَغُلاَم نَحْوِى إدَاوَةً وَعَنْزَة فَيَسْتَنْجِى بِالمَاءِ".