[Machine] I heard Anas saying that the Messenger of Allah ﷺ used to go to the bathroom and I would follow him along with a young boy from the Ansar, carrying a container of water, so he would clean himself with it after defecating. This narration is found in Sahihayn (i.e. Sahih Bukhari and Sahih Muslim) from the hadith of Shu'bah ibn al-Hajjaj.  

سَمِعْتُ أَنَسًا يَقُولُ كَانَ رَسُولُ اللهِ ﷺ يأْتِي الْخَلَاءَ فَأَتَّبِعُهُ أَنَا وَغُلَامٌ مِنَ الْأَنْصَارِ بِإِدَاوَةٍ مِنْ مَاءٍ فَيَسْتَنْجِي بِهَا مُخَرَّجٌ فِي الصَّحِيحَيْنِ مِنْ حَدِيثِ شُعْبَةَ بْنِ الْحَجَّاجِ  

The Prophet ﷺ said: The following verse was revealed in connection with the people of Quba': "In it are men who love to be purified" (ix.108). He (AbuHurayrah) said: They used to cleanse themselves with water after easing. So the verse was revealed in connection with them. (Using translation from Abū Dāʾūd 44)   

عَنِ النَّبِيِّ ﷺ قَالَ نَزَلَتْ هَذِهِ الْآيَةُ فِي أَهْلِ قُبَاءَ {فِيهِ رِجَالٌ يُحِبُّونَ أَنْ يَتَطَهَّرُوا} [التوبة 108] قَالَ كَانُوا يَسْتَنْجُونَ بِالْمَاءِ فَنَزَلَتْ فِيهِمْ هَذِهِ الْآيَةُ  

[Machine] When this verse was revealed, the Messenger of Allah ﷺ sent a message to Uwaim bin Sa'idah and said, "What is this purification that Allah has praised you for?" He replied, "O Messenger of Allah, no man or woman among us goes to the bathroom without washing their backside, or he said, their private parts." The Prophet ﷺ said, "This is the practice of Hudaifah bin Al-Yaman as narrated from him, and it is also the Sunnah (tradition) of Aisha, may Allah be pleased with her, that a woman washes her private parts before intercourse."  

لَمَّا نَزَلَتْ هَذِهِ الْآيَةُ بَعَثَ رَسُولُ اللهِ ﷺ إِلَى عُوَيْمِ بْنِ سَاعِدَةَ فَقَالَ مَا هَذَا الطُّهُورُ الَّذِي أَثْنَى الله عَلَيْكُمْ بِهِ فَقَالَ يَا رَسُولَ اللهِ مَا خَرَجَ مِنَّا رَجُلٌ وَلَا امْرَأَةٌ مِنَ الْغَائِطِ إِلَّا غَسَلَ دُبُرَهُ أَوْ قَالَ مَقْعَدَهُ فَقَالَ النَّبِيُّ ﷺ فَفِي هَذَا وَرُوِيِّنَا عَنْ حُذَيْفَةَ بْنِ الْيَمَانِ أَنَّهُ كَانَ يَسْتَنْجِي بِالْمَاءِ إِذَا بَالَ وَعَنْ عَائِشَةَ ؓ مِنَ السُّنَّةِ غَسْلُ الْمَرْأَةِ قُبُلَهَا