@thofheinz I was partially joking, but I'd be lying if I said I wasn't genuinely skeptical when it comes to this sort of thing. Just for clarity, though, I wasn't trying to imply that a lesbian is any less of a lesbian if she's dated a boy before. I'm sure that's a common thing, given the societal paradigms/pressures behind it. Even if Mako did like boys, that could just make her bisexual for all I know. I've experienced a few bait and switches in other series, or perhaps perceived them that way on my own because I was salty, and am sometimes unsure of whether or not there will ever be any actual payoff outside of teasing.
In my experience, there will usually be a girl or two who pretty much blatantly likes girls or likes a girl in the story (even if it's played for laughs). The others will pretty much give you good reason to think the same, or at least give you a faint idea of it until the author throws in something about boyfriends out of nowhere. I feel like authors don't just throw these things in for no reason. That doesn't necessarily mean the reason is that the girl is actually straight, because there's times when these scenes are used to lend to the contrary (almost like the way it's used with Ucchi here), but I never put it past me.
Yoshida and Mako would be a great pair as far as I'm concerned, and I'm not dead seriously saying this would kill the chances of any more stuff between them, but I could also see the author moving into the territory of Yoshida liking Tomoki or something like that. It could be mere paranoia on my end.