Old children's book is going viral after a very NSFW discovery

Sneaking adult humour into shows or books aimed at kids is certainly not a new thing — but it's not often you get a scene quite as eyebrow-raising as the one below.

SEE ALSO: Netflix has pulled this children's show after a very NSFW discovery

On Sunday, Ed Brody tweeted the following images from a Biff, Chip and Kipper book.

Okay, let's go in for a closer look.

Image: twitter/@chiefbrody1984

Nothing too unusual in that first one, right? Just three friends having a chat in the park.

But then, when we move on to the next scene...

Image: twitter/@chiefbrody1984

Yep: the implications in that one seem pretty unambiguous.

It turns out this isn't the only adult reference that's been snuck into Biff, Chip and Kipper books, either.

(In case you missed it, take another look at the letters on the building blocks.)

WATCH: Someone broke down the color psychology behind your favorite Disney characters

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