Funning isn't a word in English, at least not in Canada. We say "having fun." Funny is something that makes you laugh.

'funning' means the same thing as 'joking (around)' - we almost never say "funning" in America - it's very rare. funny is like 幽默的 ...

I couldn't use the word "funning" seriously - we don't use it either; it sounds like badly-constructed English. One never says "to fun" as a verb anyway.