Children used to be brought to the Messenger of Allah ﷺ so he could pray for them. Once a young boy was brought to him and urinated on him. The Messenger of Allah ﷺ said, "Pour water over it generously."
حدثنا أبو معاوية حدثنا هشام بن عروة عن أبيه
كان رسول الله ﷺ يؤتى بالصبيان فيدعو لهم وإنه أتي بصبي فبال عليه فقال رسول الله ﷺ صبوا عليه الماء صبا