In writing the term 'on the nose' is used a lot and the consensus is that things shouldn't be on the nose. Instead, their should be subtext.

How does this apply to humour? I'm thinking of humour writing, possibly satire, but it could apply to any type.

I dunno about that. If I write that someone or something is "a bit on the nose" it is a polite way of saying they stink. For example: "Your script is a bit on the nose." "Grandma's deceased dog is a bit on the nose, we'd better bury the bastard."

Now, some writing gurus have hijacked the term "on the nose" to mean flat expository dialogue that "tells" rather than "shows".

As for humour, depends whether you're writing a one-liner or a comedy show. Radio or video. Economy of words is great, but it's generally better to show than tell. And break the rules when common sense tells you to.

Kenneth puts it perfectly.

Thanks Kenneth!