@tae_ka_pre I would have thought the same, but considering he still stood there as she shouted that it was a poem about a chewing gum, it is safe. Maybe he realizes his feelings for her (except there are none, but authors can inject such frivolous things whenever the story demands it, and it has been leaning to that direction for a while now) as he realizes he was anxious before she "explained" it was just a poem exchange.
I wonder a bit though about what he thinks of them telling poems though, I got a feeling he is gonna whip out his own notebook full of them, and reduce them to tears by somehow his being really touching. Feels like it works with the flow, characters, and would be quite funny.