Musannaf Ibn Abi Shayba 9:1138

Ibn ‘Uyaynah narrated to us, from al-Zuhri, from ‘Urwah, from ‘Aishah, who said: My paternal uncle through breastfeeding, Aflah, the brother of Abu al-Qu’ays, came to me seeking permission to enter upon me after the hijab had been imposed. I refused to grant him permission until the Messenger of Allah (peace and blessings of Allah be upon him) entered, and he said: "He is your paternal uncle, so grant him permission." I said: "The woman breastfed me, but the man did not breastfeed me." He said: "May your hands—or your right hand—be covered in dust."