It was narrated from Abu Qatadah that the Messenger of Allah (ﷺ) said:"When any one of you drinks, let him not breathe into the vessel, and when he goes to the toilet let him not touch his penis with his right hand, nor wipe himself with this right hand."
أَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ أَنْبَأَنَا هِشَامٌ، عَنْ يَحْيَى، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ، عَنْ أَبِي قَتَادَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا شَرِبَ أَحَدُكُمْ فَلاَ يَتَنَفَّسْ فِي إِنَائِهِ وَإِذَا أَتَى الْخَلاَءَ فَلاَ يَمَسَّ ذَكَرَهُ بِيَمِينِهِ وَلاَ يَتَمَسَّحْ بِيَمِينِهِ " .
Nesai
The Book of Purification • Hadith 47