"Sahla bint Suhayl who was the wife of Abu Hudhayfa, and one of the tribe of Amr ibn Luayy, came to the Messenger of Allah (ﷺ) and said, 'Messenger of Allah! We think of Salim as a son and he comes in to see me while I am uncovered. We only have one room, so what do you think about the situation?' The Messenger of Allah (ﷺ) said, 'Give him five drinks of your milk and he will be mahram by it.' She then saw him as a foster son. A'isha umm al-muminin took that as a precedent for whatever men she wanted to be able to come to see her. She ordered her sister, Umm Kulthum bint Abi Bakr as-Siddiq and the daughters of her brother to give milk to whichever men she wanted to be able to come in to see her. The rest of the wives of the Prophet (ﷺ) refused to let anyone come in to them by such nursing. They said, 'No! By Allah! We think that what the Messenger of Allah (ﷺ) ordered Sahla bint Suhayl to do was only an indulgence concerning the nursing of Salim alone. No! By Allah! No one will come in upon us by such nursing!'
"This is what the wives of the Prophet (ﷺ) thought about the suckling of an older person."
Arabic : Book 30, Hadith 1287