i like you, like you not, like you

Everyday is still a rock n roll time with each other.  During the early days when they have yet mouth their first words, they fight at the slightest brush of physical contact. 

And now?  My FIL calls them "sensitive".   A single word could swiftly fire up to a  battle of punches, slaps and kicks.  All is bygones in an hour's time.  I await for the day, they can behave like civilised kids of loving parents.