Mishkat al-Masabih
Mishkat al-Masabih 354
How to act when relieving oneself - Section 2
Arabic hadith text
وَعَن عبد الله بن سرجس قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لَا يَبُولَنَّ أَحَدُكُمْ فِي جُحْرٍ» . رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ
Translation
'Abdullah b. Sarjis reported God’s messenger as saying, "None of you must pass water in a [snake's] hole". Abu Dawud and Nasa'i transmitted it.