Musnad Ahmad 1007:6

'Abd al-Wahhab al-Thaqafi narrated to us, from Ayyub, from Yahya ibn Abi Kathir, from Ibn Abi Qatadah, from his father, that the Prophet, peace and blessings of Allah be upon him, forbade breathing into the vessel, or touching one's private part with one's right hand, or cleaning oneself with one's right hand.