Sahih al-Bukhari 6002
Narrated `Aisha:
The Prophet (ﷺ) took a child in his lap for Tahnik (i.e. he chewed a date in his mouth and put its juice in 
the mouth of the child). The child urinated on him, so he asked for water and poured it over the place 
of the urine.
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ هِشَامٍ، قَالَ أَخْبَرَنِي أَبِي، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم وَضَعَ صَبِيًّا فِي حِجْرِهِ يُحَنِّكُهُ، فَبَالَ عَلَيْهِ، فَدَعَا بِمَاءٍ فَأَتْبَعَهُ‏.‏