Sahih Muslim 14527
In-book no 7250وَحَدَّثَنَاهُ يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا وَكِيعٌ، عَنْ إِسْمَاعِيلَ بْنِ أَبِي خَالِدٍ، بِهَذَا الإِسْنَادِ وَقَالَ حَتَّى إِنْ كَانَ أَحَدُنَا لَيَضَعُ كَمَا تَضَعُ الْعَنْزُ مَا يَخْلِطُهُ بِشَىْءٍ .
This hadith has been narrated on the authority of Isma'il b. Khalid with the same chain of transmitters and the words are: " One amongst us would relieve himself as the goats do without anything mixing with its excrement."