[Cyph0n]

I don’t think inserting innuendo is necessary. In fact, I personally find it distasteful and nothing more than an easy way out.

I think the proper way to do it is to include themes and/or characters that adults would relate with too. Ghibli movies are one example where this is done well (most of the time).

[sanderjd]

Bluey doesn't do it as innuendo either. I like Bluey and Ghibli the most of all children's media I'm familiar with, for exactly this reason.