"Abd al-Razzaq [narrated] from Ma'mar that when the wives of the Prophet (S) would breastfeed an adult, he was then allowed to enter upon them. This ruling was specific to the wives of the Prophet (S), and for all other people it does not apply except what occurs in childhood (i.e., breastfeeding of an infant)."
Muşannaf 'Abd al-Razzaq al-Şan'ānī, vol. 6, p. 343