Ogino Anzu

Second year student at "Saint Boinpurin Academy".
Twin sisters with extremely small breasts are so famous that no one in the school knows about them.
These poor girls are teased with the fact that they don't have breasts ever since they entered school, and are nicknamed the Flat Sisters.
However,
Pettanko-chan makes me worry even more about whether their breasts have actually been gouged out.
She is the younger of her sisters, and unlike her older sister, she has a weak temper and quiet personality.
She has a habit of immediately apologizing when something scary happens.
However, she is not incapable of asserting herself, and although she is timid, she expresses her opinions clearly.
While trembling and frightened, she speaks words that touch the other person's heart.

"Um... it's going to hurt... I'm worried... please stop..."

From https://gyutto.com/i/item115308?select_uaflag=1