When thinking up cartoon ideas (and I'm sure most cartoonists do this) I think of the situation or gag, come up with a suitable caption and then envisage the final artwork. If the image doesn't work then you try it another way and usually you get the image right but sometimes, just sometimes, you have to let the gag go because you can't come up with a suitable image i.e. it just desn't work. Then it's the caption's turn and I find that I usually stick with the very first caption I come up with. I was talking to one well known cartoonist who told me that they NEVER use the original caption and always fine "tune it"....
When drawing or doodling in a sketchbook on the other hand the image obviously materialises first and I start playing the 'think of a caption' game to suit the image. These are never good enough to sell but I find it an amusing pastime. So, I drew the image below one day and came up with the caption "When a chimney sweep cleans his teeth". Not hilarious, obviously, but quite a humorous image. It could also be called "When you push things too far!"
Then I started to analyse the gag itself (always a humour killer this one!) and wondered whether a chimney sweep would actually clean his teeth this way around i.e. wouldn't he do it the other way around? So I came up with the image below:
NOT a humorous image - quite obscene actually but I do prefer the drawing!