@Daxes I thought it was "Because he's her man?" As in the girls realize Himeno-chan likes Ouji, and she wanted to apologize/say goodbye to him. Him being the only boy she invited to her birthday party made that really clear to all the other girls, even if Ouji hasn't figured it out yet.
Same shit happened to me too
I was the only boy in my neighbour birthday party
And I was stuck feeding french fries to some 5year old girl and she licked my finger
"How was it called, when it's one boy surrounded by girls... ISOLATION".
You're not wrong, m'boy. There's a more interesting name too, but it's a few years too soon
For real tho, I know the feeling. It was awkward as fuck.
Mom and Onee-chan sure seemed to enjoy it tho XD
And she chased after him to apologize. Can other tsunderes learn from her? Please?