Narrated Abu Qatada: The Prophet 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 ."
Hadith ReferenceSahih Bukhari / The Book of Wudu (Ablution) / Hadith: 154
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة