He, sallallaahu 'alayhi wa sallam, played with children and made them laugh:
Ya'laa ibn Murrah (a Companion) narrated that some people went with the Prophet of Allah, sallallaahu 'alayhi wa sallam, to an invitation for dinner, and on the way they found Al-Husayn playing. So the Prophet of Allah, sallallaahu 'alayhi wa sallam, went ahead of the people and put his arms out, and Al-Husayn would run away laughing, until the Prophet of Allah, sallallaahu ‘alayhi wa sallam, finally picked him up. He then put one of his hands on Al-Hasan's chin, and the other on the back of his head and then kissed him.
Then he, sallallaahu 'alayhi wa sallam, said: "Al-Husayn is from me, and I am from Al-Husayn, may Allah love whoever loves Al-Husayn, Al-Husayn is a nation on his own."
Al-Mubaarakpoori (a scholar) said: “The words: "Husayn is from me, and I am from Al-Husayn" mean that they are connected in such a way that it could be said that each one is from the other.
The words: "Al-Husayn is a nation on his own:" i.e. in doing good deeds, or the meaning could be his many offspring will form tribes, so it is a reference that his many descendents will last, and they still exist until this day.