Abdullah bin Abi Qatadah al-Ansari narrates from his father that he heard the Messenger of Allah (peace and blessings be upon him) say: "When one of you urinates, he should not touch his private part with his right hand, nor clean himself (istinja) with his right hand, nor breathe into the vessel."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14654