(19) باب لاَ يُمْسِكُ ذَكَرَهُ بِيَمِينِهِ إِذَا بَالَ
Narrated Abu Qatada:
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 ."
Reference: Sahih al-Bukhari 154
In-book reference: Book 4, Hadith 20
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 4, Hadith 156