Sahih Muslim Book - 2, Hadith - 613

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى أَخْبَرَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ عَنْ هَمَّامٍ عَنْ يَحْيَى بْنِ أَبِي كَثِيرٍ عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ عَنْ أَبِيهِ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَا يُمْسِكَنَّ أَحَدُكُمْ ذَكَرَهُ بِيَمِينِهِ وَهُوَ يَبُولُ وَلَا يَتَمَسَّحْ مِنْ الْخَلَاءِ بِيَمِينِهِ وَلَا يَتَنَفَّسْ فِي الْإِنَاءِ.

It was narrated from 'Abdullah bin Abi Qatadah that his father said: "The Messenger of Allah (s.a.w) said: 'None of you should hold his private part in his right hand when he is urinating, nor wipe himself with his right hand after defecating, or breathe into the vessel (while drinking)."'