Sahih Bukhari Volume 008, Book 073, Hadith Number 031.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 73. Good Manners and Form (Al-Adab)
Narated By 'Aisha : The Prophet 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.