From Sahih Muslim (Hadith 662):
A'isha, the wife of the Apostle (ﷺ) said:Babies were brought to the Messenger of Allah (ﷺ) and he blessed them, and after having chewed (something, e. g. dates or any other sweet thing) he rubbed there with their soft palates. A baby was brought to him and he passed water over him (over his garment), so he asked water to be brought and sprinkled it, but he did not wash it
Reference: Muslim 662