Sunan Ibn Majah, Book 1, Hadith 365 (In-Book) ⓘ
It was narrated that Ibn 'Abbas said: "The Messenger of Allah turned towards a mountain pass and urinated, until I took pity on him because of the way he parted his legs when he urinated."
حَدَّثَنَا مُحَمَّدُ بْنُ عَقِيلِ بْنِ خُوَيْلِدٍ، حَدَّثَنِي حَفْصُ بْنُ عَبْدِ اللَّهِ، حَدَّثَنِي إِبْرَاهِيمُ بْنُ طَهْمَانَ، عَنْ مُحَمَّدِ بْنِ ذَكْوَانَ، عَنْ يَعْلَى بْنِ حَكِيمٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ عَدَلَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ إِلَى الشِّعْبِ فَبَالَ حَتَّى أَنِّي آوِي لَهُ مِنْ فَكِّ وَرِكَيْهِ حِينَ بَالَ .
also referenced under: Hadith 341 (Reference) & Volume 1, Book 1, Hadith 341 (DarusSalam)