Sayyidah Aishah (may Allah be pleased with her) said: Children used to be brought to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) would supplicate for blessing for them and do tahnik for them (soften a date and rub it on the palate). A child was brought, and he urinated on him (peace and blessings be upon him). He (peace and blessings be upon him) called for water and sprinkled it over it, and did not wash it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4153