The thing with Ibuki Sumire is, she can transform into any person. Normally she is a cold beauty with a bit of a playful personality. But there are occasions like this where she is childish.
Yuhi didn't mind that side of her; it makes her human, it makes her feel alive. He doesn't know much about the time she isolated herself because of Mamoru's death. But he could imagine what she was like that time. There were moments in the past where she became that way.
He was patiently waiting for her as she lined up to buy some crepes. Initially, he offered to buy them for her, but it somehow ended up this way.
These days she is more cheerful and outgoing. She smiles a lot more. This is what he wanted from her. But now that she has reached this stage, Yuhi knew that she would have to proceed to the next step swiftly.