Sayyiduna Anas bin Malik (may Allah be pleased with him) said: I took my brother to the Prophet (peace and blessings be upon him) so that he (peace and blessings be upon him) could perform tahnik for him (put chewed date in his mouth). I saw him (peace and blessings be upon him) inside a pen, branding sheep. The narrator said: I think he said: on their ears.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13264