Currently reading the webnovel for this manga I'm a bit confused as at some point, the plot of the novel and the manga seemed to have diverged radically. Anyone who read the novel had the same experience?
On the topic of consent, I think the novel, by virtue of having extensive passages of Wakaba's internal monologue makes it a bit easier to understand and I do think that the tag of "dubious consent" is definitely the most appropriate as Wakaba herself is just constantly confused about why she does not push back against Komaki. She even acknowledges that she probably could just stop interacting with her but just plain doesn't want to do that and like 70% of the novel is just her trying to puzzle out what her relationship to and thoughts about Komaki actually are.
In short, it is dubious because Wakaba herself actually doesn't really know if she's consenting.
One thing I do find significant though and that sets this one apart from 100 days in my personal opinion is that there's still a sort of invisible line not to be crossed, despite what that previous poster with the panels might want to suggest. The tone in the novel too gets noticeably darker when Komaki first makes Wakaba undress and Wakaba is genuinely scared of what might happen, resolving that any actual sexual acts with Komaki would be a step too far and something she would need to resist. The fact that Komaki then DOESN'T step beyond that red line is significant I think, as it defuses the dark tension which has been INTENTIONALLY built up before that and implies that Komaki might, despite her demeanour, not be willing to do anything that would actually emotionally harm Wakaba.
In 100 days, on the other hand, that line is crossed in the infamous chapter mentioned by others here. Of course, the violated party then decides that she actually doesn't mind the line being crossed during/after the process, but it doesn't change the fact that that boundary was violated. I understand that we each have our own feelings about that scene and our distinct opinions, but as someone who was emotionally disturbed by that scene and had to drop the manga because of it, I personally (!) struggle to understand how it can be read as anything but rape, and if I had had that tag at the time of my reading the chapter, I might have been more emotionally prepared for what's to come and it wouldn't have been so disturbing. In any case, that doesn't mean people aren't allowed to enjoy that manga or have different readings of the scene, but I do think it is different than for example this story and I wonder if fans of 100 days aren't influenced in their reading of the scene by their knowledge about the (apparently plentiful) fluff to come later down the line.