I am not confident at all on kogasa's line about her chest, so translation check please!
When you have a big chest, your shoulders are stiff, it gets in your way, buttons burst open...When did you...So-SO SORRY!Ducks go quack~
Ducks go quack~You've got a nice figure, Sanae-san.Since you're an umbrella, maybe that's why you're so skinny?... Sorry about that.I feel like I'm all skin and bones somehow, and I have no chest...Worrying so much... you're just normal, aren't you?If anything, wouldn't them getting too big be scary?Huge!!