(a) It is narrated from Sayyiduna Abu Qatadah (may Allah be pleased with him) that he (peace and blessings be upon him) said: "When one of you urinates, he should not touch his private part with his right hand, nor breathe into the vessel, nor clean himself with his right hand."
(b) In one narration: "None of you should ever hold his private part with his right hand while urinating."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 543