@phoenix_eD it's everyone's way of bringing up something because they're flustered. Itsuki was clearly flustered when she brought it up during her encounter with Fuutaro outside of the restroom, Yotsuba talked about it when she saw Fuutaro, so did Nino, and at the end, Fuutaro also brought it up...
@Mick96
This was the manga that was released at the time the game Toaru Majutsu no Virtual-On was released for the purpose of promotion. A light novel was also released as well.