"Well, I could just go find somebody to get me pregnant the old-fashioned way," says Tony. "Wouldn't be the first time that kind of thing happened in a royal family. Although it might be the first time the queen's spouse couldn't get her pregnant because they were also a queen."
"I am developing a mental image of the political proposal. I'm kind of stumped about how to picture the domestic one," observes Bella after a moment.
"Yes, see, that's what's puzzling me. Do I just not know enough twins, because I didn't think this was a way twins worked either, so maybe it's just you, or something?"
"I do not get the impression that this is how other sets of twins work," says Sherlock. "But I don't consider that relevant."
"So the way this particular set of twins work is that you would be perfectly okay to be both married to me," Bella clarifies. "...And the 'old fashioned' backup plan, about that, would this be if I were or were not married to you at that point?" she asks Tony.
"I don't really know," says Tony. "I mean, if I was married to you and then we found out we needed to do it, I think it would be a bad plan for me to stop being married to you and then go and get pregnant and come back and marry you again."
"Yes, that seems obviously silly," agrees Bella. "But, like, maybe this would go over better with parties who are concerned about succession if I married one of you and then worked on the probably-minor-technical-issue with that one of you and only married the other one if I got it to work? And if I can't get it to work then the other one has to find a husband, but I can do, you know, a husband window."
"That sounds very practical," says Sherlock. "Which one would you like to marry first?"
"I don't know!" Bella throws up her hands, laughing. "I only found out you liked me five minutes ago. I only found out Tony liked me beyond general flirtatiousness a few more minutes ago than that."
Write write write.
Because the "next" question may not have been fully answered yet, but it appears to involve talking about getting married, so Bella thinks she can risk it!
And Bella writes in her notebook. This page is shaping up to look like a two-column chart with things like "nnnng" and "design!" in one column and "2 days!!!" and "queen M?!" in the other.
Notebook down, specs on, look of utter fascination.
And Sherlock's armour peels itself off of her and folds up tightly into a neat little bundle.
She practically dives into her notebook when the armor is all wrapped up in itself and her specs are back in her hat. She circles two things in the column on the left and writes under them "royal magic" and "sword" and then in the margin "boy am I ever grabby; to-fix?" and then in the column on the right "two of them!" and then in the column on the left "two of themmmmm".
"Uh, pros and cons, basically," says Bella, squirming a little. "It's a complicated subject, I have complicated opinions, I'm trying to break them up into little bits so I can weigh them and see if any of the cons can be patched and whether the pros add up to enough."
"The fact that there's two of you is in both columns," she volunteers after a moment. "I've never seriously considered a - plural arrangement before."