أَخْبَرَنَا هَنَّادُ بْنُ السَّرِيِّ، عَنْ وَكِيعٍ، عَنْ هِشَامٍ، عَنْ يَحْيَى، - هُوَ ابْنُ أَبِي كَثِيرٍ - عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ، عَنْ أَبِيهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا دَخَلَ أَحَدُكُمُ الْخَلاَءَ فَلاَ يَمَسَّ ذَكَرَهُ بِيَمِينِهِ " .
It was narrated from 'Abdullah bin Abi Qatadah that his father said: "The Messenger of Allah (PBUH) said: 'When any one of you enters Al-Khala' (the toilet), let him not touch his penis with his right hand.'" Translation Not Available
Book Ref: Sunan An Nisai Book 1 Hadith 25
Web Ref: Sunan An Nisai Vol 1 Book 1 Hadith 25