"My father told me that he heard the Messenger of Allah say: 'When anyone of you urinates, let him not touch his penis with his right hand nor clean himself with his right hand.'" Another chain with similar wording.  

أَنَّهُ سَمِعَ رَسُولَ اللَّهِ ﷺ يَقُولُ إِذَا بَالَ أَحَدُكُمْ فَلاَ يَمَسَّ ذَكَرَهُ بِيَمِينِهِ وَلاَ يَسْتَنْجِ بِيَمِينِهِ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ إِبْرَاهِيمَ حَدَّثَنَا الْوَلِيدُ بْنُ مُسْلِمٍ حَدَّثَنَا الأَوْزَاعِيُّ بِإِسْنَادِهِ نَحْوَهُ  

"I heard 'Uthman bin 'Affan say: 'I never sang a song or told a lie or touched my penis with my right hand after I swore on oath of allegiance to the Messenger of Allah to that effect.'"  

سَمِعْتُ عُثْمَانَ بْنَ عَفَّانَ يَقُولُ مَا تَغَنَّيْتُ وَلاَ تَمَنَّيْتُ وَلاَ مَسِسْتُ ذَكَرِي بِيَمِينِي مُنْذُ بَايَعْتُ بِهَا رَسُولَ اللَّهِ ﷺ  

"The Messenger of Allah said: 'When anyone of you cleans himself, he should not clean himself with his right hand. Let him clean himself with his left hand.'"  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا اسْتَطَابَ أَحَدُكُمْ فَلاَ يَسْتَطِبْ بِيَمِينِهِ لِيَسْتَنْجِ بِشِمَالِهِ