Not sure how exactly to explain it.
The innovation it is celebrating is that the drawing is in the shape of a dick and balls. But the underlying drawing itself (NOT cock-shaped) is something that kids have been drawing in books/notebooks/engraving on desks for years and years and years. It probably has a name (or at least a reference), but I don't know it, and wouldn't know how to Google it effectively.
Show it to your son, he might be able to tell you better than me lol