The Prophet ﷺ said, "Whenever anyone of you makes water he should not hold his penis or clean his private parts with his right hand. (And while drinking) one should not breathe in the drinking utensil ."  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا بَالَ أَحَدُكُمْ فَلاَ يَأْخُذَنَّ ذَكَرَهُ بِيَمِينِهِ وَلاَ يَسْتَنْجِي بِيَمِينِهِ وَلاَ يَتَنَفَّسْ فِي الإِنَاءِ