Messenger of Allah ﷺ said, "Whenever anyone of you drinks water, he should not breathe in the drinking utensil, and whenever anyone of you goes to a lavatory, he should neither touch his penis nor clean his private parts with his right hand." (Using translation from Bukhārī 153)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ «إِذَا شَرِبَ أَحَدُكُمْ فَلَا يَتَنَفَّسْ فِي إِنَائِهِ وَإِذَا أَتَى الْخَلَاءَ فَلَا يَمَسَّ ذَكَرَهُ بِيَمِينِهِ وَلَا يَتَمَسَّحْ بِيَمِينِهِ»