Not overbearing, I would say, in the case of the Mother Box, but on the contrary - everything that is positive about the feminine in its aspect of mother - nurturing, caring, healing, protecting, even teaching and developing - and nothing of the negative. An idealisation that is problematic, of course, because the absence of female counterparts to both Highfather and Darkseid - all candidates are either killed off or eliminated in some other way - is a significant aspect of the whole conception.

IOW, the feminine - even moreso on New Genesis than on Apokalips, disturbingly - has been sublimated away and concentrated into the form of Mother Box: always there to provide all those necessary services mentioned above, but having no troubling persona or will of her own to get in the way of the male heroes. This is one reason why Barda is such an important character in the whole New Gods concept - and, in Hunger Dogs, Bekka.

So for me, if the textbook was thinking of "Mother Box" as referring directly to the female sexual organs, as the question it asks seems to have in mind, I think it was on the wrong track, notwithstanding the fact that "box" is (or was when I was young) a slang term for vagina. "Mother Box" in no way functions as that kind of low-level sexual innuendo.

Similarly "Boom Tube" doesn't look to me the crude sort of phallic symbol the textbook question might appear to imply - i.e. a symbol of male sexual potency and by, er, extension (hard to avoid these unintended double entendres), male power in general. But on another level it may well function as a symbol of the unbridled technology that develops in a world in which the feminine has been in some sense subordinated - and the New Gods are always gods of technology, among other things.  

There's a lot more to say about the ideas raised here but I'll save it for that hypothetical future New Gods review thread.

I think the main reason, and I think there is sort of a consensus on this (I've read a crap load of "Kirbyana" in the JKC over the years (owning most of the run, and continuing to subscribe to it), is that in the scheme of the DC Universe Kirby's Fourth World was always an outlier.

The whole epic story came, from its guts to it's extremities, from the inimitable imagination of Kirby. And Kirby alone. It was a thing unto itself, and despite the somewhat forced presences and appearances of Superman, Jimmy Olsen and Dead Man it was ever of the Kirbyverse much more so than the DC Universe proper.

And it was this unheard of interconnecting quartet of books (at least it strived to be that way) that amounted to another concept alien to the DC way of things.

Additionally, the whole thing still looked like a Marvel book. DC was never comfortable with not only what Jack was doing (in his own way and in his own mind) but with how he was doing it, how he was drawing it. House styles were much more significant in those days.

When sales began to soften and I think Carmine Infantino, and the rest of the DC powers that were, acted on their gestating nervousness and growing instincts and killed the Fourth World. Kirby was ahead of his time and faced with an establishment that just didn't "get it."

As to the etymology of phrases like boom tube and mother box I think Cei-U is on the right track. Kirby loved wordplay and the sounds various made when strung together. He loved coming up with names and neologisms.

Also, the Fourth World was in part an attempt to tap into the popular culture of the day and the expression "mother box" does sound as it could come from the lexicon of the hippy or Age of Aquarius. Even the boom tube sounds it to my ears. I doubt very much Kirby had in mind any sexual subtext, although it makes for interesting speculation.

I don't know much about Kirby's early life or his biography in general, but I'm not aware of any absence of mother-figures in his childhood, so I wouldn't trace the mother-box concept to any personal psychology of that sort.

Although, having said that, I can think of two important areas of his adult life in which the effective absence of any feminine presence is notorious: the army and comics. I would say that there is probably a connection between those experiences and how the feminine aspect of things is handled in the New Gods.

For me, the important thing Kirby was getting across with the term Mother Box is the idea of a technology that is more than just technology as we usually thing of it - a technology that is alive. Mother Box is a living computer, among other things. I wonder if younger readers remember that he came up with the idea and the term before the advent of the personal computer (sometimes referred to as a box itself come to think of it).

Kirby was very close to his mother. He came from an immigrant tradition that heaped a sacred respect upon the maternal. He relates, almost a cliche really, how all the gangs that vied for ascendancy in the Lower East Side, populated by immigrant families, could beat each other black and blue and still hang our the next day, but could not insult the mothers of their members and get away with it.

Kirby also tells how, in connection with your musings berk, his mother imbued him with those storytelling skills he brought to his life in comics. She was a storyteller herself, relating the fables and folktales to a young Jakob Kurtzberg at bedtime, leaving a remarkable and abiding impression on the future King of Comics.

That's would be an interesting team-up!

It would be very interesting to see someone gain the rights to ALL the Kirby properties and intertwine them. Eternals always felt to me like it belonged somewhere in the Fourth World.