More like little sister play. Erotic.
In all seriousness, it is not just that, when Sakurai sensei was asked for a second time why she liked Tachibana sensei, she added a "?" The her little sister response. Even the teacher from class C realizes that Sakurai isn't even aware of her feelings.
Poor Tachibana sensei, she thinks that her love is unrequited.
I don't think she actually got sister zoned. At first Sakurai did say she reminded her of her sister but at the end we can see how uneasy and embarrassed she is. Her feelings are definitely evolving!! And thanks for the tl!
RIP, buddy got sis-zoned
Worry not, little grasshopper, for there is still hope in the horizon
That "I think", and some other stuff, to be specific. At least Im glad that she already knows she likes her