Mystical Debris

After that, Sorachi had to address major plot points throughout the next three arcs. Gintoki and Takasugi's fight, the Shogun's death, the Shinsengumi disbanding, Utsuro's rise as the final villain, Kagura and Kamui's showdown, the reunion of the Joui 4...

All of these things were crucial to the plot, but took a long time to unfold. Finally, when Tsukuyo reappeared in Silver Soul arc, a lot of time had passed (lesson 620, over a hundred chapters later). And the first thing Sorachi chooses to do is to have her help Gintoki and make a sex joke. Ok, nothing new in this manga, I guess.

But what was surprising was this one heavy panel that people wouldn't stop talking about at the time, because it really left no room for interpretation. Yes, it was Hinowa who said it, but, again, this was written by someone, and that someone didn't intend this to be a light tease.

Sorachi had no need to do so if he'd already closed the door on future possibilities between them and we already knew she'd feelings for him. And yet, he dedicated several pages to showing the struggle she'd with leaving Yoshiwara to go help Gintoki and the rest of her friends in Kabukicho.

In LP she realized she was in love, but she still felt embarrassed and stupid because of it, and Kyuubei had to tell her hey, it's ok. Throughout the series, although Tsukuyo loves Gintoki, she often needed reasons to be with him. Sometimes it was because of her duty as Yoshiwara's guardian, sometimes because she's with her girl friends, sometimes even Hinowa created these reasons. But this chapter addresses how dumb it is. In LP arc, Gintoki was around just because.

In other words, at this point, Sorachi continued to develop their relationship, even after that arc. But did something else happen?

Well, after a while, when Gintoki was resting peacefully on his futon, Sorachi has Tsukuyo conveniently trip over a damn bottle containing alcohol right next to the guy, all during a dialogue explaining how in times of power outages and such, the population increases. So the joke here was that they would fuck and Gintoki would get her pregnant like heyooo? (ch. 628).

But that would be it? Their last moment being a high-caliber sex joke before the end of the manga?

The thing is... the manga didn't end there lol it lasted about 70 more chapters. Here Sorachi once again needed to address some loose plot ends before finishing the series that took priority, like Gintoki and Takasugi's bond and what would happen with Shouyo/Utsuro.

We might think that there're no loose ends between Gintoki and Tsukuyo anymore. We already know she's in love with him, so why bother?

HOWEVER Sorachi once again decided to hit us with something (and quite sappy this time, in a good way)...

When they meet again, there's a flashback in which Gintoki leaves and Hinowa asks Tsukuyo why she didn't follow him (ch. 686). She replies that she decided to stay because yes, she has a duty, but the main reason was to tell him what had happened in his absence... LITERALLY THERE WAS NO NEED FOR IT TO BE SO CHEESY, but then again Sorachi wanted us to know what Tsukuyo had gone through and he wanted Gintoki to hear it too.

This is another way to show how real and deep her love is and how she understands what Gintoki is going through on a fundamental level. Sorachi wanted to show how Tsukuyo knows that Gintoki needed to embark on his journey alone, otherwise he wouldn't have disbanded the Yorozuya. She knows that it's important to him that someone be there and update him on what has happened, so that he feels connected to everyone again. And Sorachi chose that someone to be Tsukuyo, making explicit how she's an anchor for Gintoki here.

This time it wasn't because she needed a big reason or because she felt stupid, it was her own decision, which is huuuge for her and what could happen.

So now that she knows for sure he's in Edo, she's going to help him with everyone else. There's also the idea of endings and new beginnings that Tsukuyo talks about, which could also apply to her dynamic with Gintoki, but that's a talk for another day.

The last thing to mention is when they're at the terminal and Sacchan teases Tsukuyo about the man she loves... You know, the woman who's been stalking Gintoki since the beginning... And it's really dumb, because everyone is saying these heartfelt lines, talking about how they want to reach him, how they want to help him... and Sorachi, instead of having Sacchan tell a dirty joke about herself, like she always does, has her say something about how Tsukuyo should fuck Gintoki, or vice versa, does it matter at this point? (ch. 699).

And it's not just a sex joke as before. Contrary to the sentiment expressed in lesson 620, here Tsukuyo intends to go on living and see Gintoki again, which is something said by herself.

From what I can tell, Sorachi wanted to keep giving their relationship some form of development right up until the end. Even after committing to an open ending, the fact that he kept their dynamic in mind, even with limited interactions, just to push it forward in some way is honestly kinda sweet, ngl.

Tsukuyo isn't a character Sorachi uses a lot, probably because she's not as available as the rest of the cast living in or near Kabukicho. And yet, almost every time she appears, he develops the bond that Gintoki has with her. You can tell that some scenes, heck, even some lines, are quite deliberate to be read romantically.

If anything, we could say that the real problem was that we didn't get much from Gintoki in the last stretch, which I think could be attributed to both the in-universe context of the series and the time constraints and difficulties Sorachi faced in finishing Gintama.

(Sorry this ended up being so much longer that I intended lol.)