I feel like this manga is lying to us, we can see Kyonko got them even if they aren't big, yet they say she has none.
Albeit, without any breastsAlright!NnngIf I rub your chest, it'll get bigger!Oh, let me try too!Cut it out!Hey!
Stop!Forcing me like that...Jeez, so you finally came, Kyon!Don't worry. No one's going to notice your chest!I got enough of that in the first panel.