Musannaf Ibn Abi Shayba 27:555

Ja'far ibn 'Awn narrated to us, he said: Mu'awiyah ibn Abi Muzarrad al-Madini informed us, from his father, from Abu Hurayrah, who said: These two eyes of mine saw and these two ears of mine heard the Prophet, may Allah bless him and grant him peace, while he was holding the hand of al-Hasan or al-Husayn, and he was saying: "Ascend, 'Ayn Baqah." He said: The boy would place his foot upon the foot of the Prophet, may Allah bless him and grant him peace, then he would lift it and place it upon his chest. Then he would say: "Open your mouth." He said: Then he would kiss him, and then say: "O Allah, I love him, so love him."