ENOfficial
Narrated Mahmud bin Ar-Rabi: On whose face Allah's Messenger (ﷺ) had thrown water from his mouth, the water having been taken from their well while he was still a young boy (who has not yet attained the age of puberty).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ صَالِحِ بْنِ كَيْسَانَ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي مَحْمُودُ بْنُ الرَّبِيعِ، وَهُوَ الَّذِي مَجَّ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي وَجْهِهِ وَهْوَ غُلاَمٌ مِنْ بِئْرِهِمْ.
sunnah.com