
Just because Kashima's feelings are true doesn't make the relationship nontoxic. I've talked about it more extensively in another comment but Kashima has a tendency to force himself (even though not to the extent of the classic yaois) on Toono, like he did with the kiss. For this reason and because of his general disposition I also find Kashima to be very annoying.

I think they're talking about the kiss on the rooftop. It wasn't drawn on-panel. But Toono did say "Don't kiss me if we are not dating. Now you have kissed me twice" or something like that. While I love Kashima and I'm glad he's not as forceful as the stereotypical "tachi" in BLs, he is kinda insistent in ways Toono isn't comfortable with. And personally, Toono being so explicitly put off with Kashima's advances is such a turn off. I'm not exactly a shipper of YacchanxToono, but I prefer the way their relationship is evolving more naturally and more honestly. Even though I don't think Toono likes Yaguchi romantically, at least not anymore if he did before. This manga is kinda complicated in that regard ╮( ̄▽ ̄)╭
https://aminoapps.com/c/yarichinbitc700/page/item/vol-3-capitulo-16-5/0pMq_mdfZIK8QKX47W3xjLXn42NNRem8d4