Musannaf Ibn Abi Shayba 35:77

Ibn ‘Uyaynah narrated to us, from al-Zuhri, from ‘Ubayd Allah, from Umm Qays bint Mihsan, who said: I entered upon the Prophet (peace and blessings of Allah be upon him) with a son of mine who had not yet eaten food, and he urinated on him. So he (the Prophet) called for water and sprinkled it.