The image would have to be topical, and the sexual nature would have to be necessary (not-gratuitous) for it to be compliant with that CoC.

I'd be surprised if such an image can exist in an electronics forum because those parameters are pretty narrow. I also don't interpret policy as disallowing any form of joke.

I'm not about to go hunting, but I think I would find a good number of good non-offensive jokes, and probably no instances of sexual imagery.