"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