"No, it's--is this a translation issue or do you actually not--" his voice was already quiet but now he's barely whispering. "It's when you want to have sex."

"...I don't know what that is either."

Bruce plonks his head down on the table, with just enough presence of mind to miss the remains of his salad, and emits a muffled "Aaaaauuuuuughhhh."

"I'm sorry?"

"No, this one is definitely my fault," he informs the table. ". . . Especially if this world actually doesn't have it and it's not just you not knowing the word. But I am the worst person on this or any planet to explain." Possibly he is just the worst person on any planet, period.

"Um. Maybe we can try to find a book on it when we get to Auradon City?"

"That's. Probably a good idea."

"...uh I am still curious what it is even though you might do a bad job of explaining. I think you've always been great at explaining things to me."

Ugh ugh ugh okay in fairness he would be super frustrated if someone told him there was a thing he didn't know about and then refused to explain it. He peels himself off the table and makes solid eye contact with the air six inches above Kaleva's head. Which makes him notice the next table and the fact that there are people at it. "Can it wait until we're somewhere with fewer people around."

"Okay."

Cuddles?

Cuddles are probably safe.

And then they can talk about the countries they're passing through until they get a hotel room in Auradon City and Kaleva can sit on the bed and go "what is sex?"

Bruce is going to have this conversation while pacing. "So, uh, on Earth, when a man and a woman are married, there's a physical act they can do to express their love and commitment and it's what causes the woman to get pregnant."

"...I always thought it sort of spontaneously happened when you wanted one but no one actually told me that. I just guessed."

"Like I said, it could be different here. Do children tend to resemble both their parents?"

"Yes, yes they do. --We should probably go try to find a book about it."

"We really should." Even if that means he's going to have to admit to everything sooner rather than later. He needs to know.

They take a streetcar to a bookstore. (Lev holds Bruce's hand.)

In the Science section, the bookstore is utterly silent on the concept of reproduction.

Is there a medicine section? A parenting section that might include something with a chapter on how you become a parent in the first place?

Medicine and parenting sections are also silent.

There is, however, an Adults Only section. 

He's not an adult. Neither of them is an adult. But he has to know. (If he had been Adam, the serpent wouldn't have needed to go after Eve first. He has known this about himself for a long time.)

Is there anyone watching the Adults Only section, or can he just walk in between the shelves like he belongs there?

Yes, they can. 

The Adults Only section has a bunch of magazines and books, cryptically divided into the categories "M/M", "M/F," and "F/F." The magazines are titled things like HEALTH and FITNESS, and have smiling attractive people on the covers (men in the M/M section, women in the M/F and F/F sections). 

M and F are Male and Female, maybe? There doesn't seem to be anything in here about pregnancy or parenthood respectively. He tries one of the HEALTH magazines in the M/F section in the hope that it has anything on how to have a healthy pregnancy.

The HEALTH magazine has three pages of desultory exercise routine, a hundred pages of naked women, and one page explaining that the naked women are supposed to be inspirational to you in your quest towards fitness. 

It is sort of unclear why the doe-eyed gazing is involved. 

ACK. That is way more female nudity in two seconds of harried page-flipping than he has seen in the rest of his life put together. And no useful information whatsoever, unless it was in fine print next to the (apparently legal! in a public bookstore!) naked people pictures.

What about the non-magazine books, do any of those look like nonfiction? Without pictures?