ENOfficial
Umm Qais daughter of Mihsan reported that she came to the Messenger of Allah (ﷺ) with her child. who was not yet weaned, and she placed him in his lap; and he urinated in his (Holy Prophet's) lap. He (the Holy Prophet) did nothing more than spraying water over it.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحِ بْنِ الْمُهَاجِرِ، أَخْبَرَنَا اللَّيْثُ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنْ أُمِّ قَيْسٍ بِنْتِ مِحْصَنٍ، أَنَّهَا أَتَتْ رَسُولَ اللَّهِ صلى الله عليه وسلم بِابْنٍ لَهَا لَمْ يَأْكُلِ الطَّعَامَ فَوَضَعَتْهُ فِي حِجْرِهِ فَبَالَ - قَالَ - فَلَمْ يَزِدْ عَلَى أَنْ نَضَحَ بِالْمَاءِ .
sunnah.com