قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا شَرِبَ أَحَدُكُمْ فَلاَ يَتَنَفَّسْ فِي الإِنَاءِ، وَإِذَا أَتَى الْخَلاَءَ فَلاَ يَمَسَّ ذَكَرَهُ بِيَمِينِهِ، وَلاَ يَتَمَسَّحْ بِيَمِينِهِ ".
Abu Qatadah reported: The Messenger of Allah ﷺ said, “When one of you drinks, let him not breathe into the vessel. And when he goes to the toilet, let him not touch his private part with his right hand, nor wipe himself with his right …
also in Sahih al-Bukhari 154