Chie Satonaka, Yukiko Amagi, Rise Kujikawa and Naoto Shirogane, are all bound and (having their bare feet tickled.) being "interregated" by a mysterious party that you are a member of. You see Chie and Naoto are trying to hold their laughter, while Yukiko and Rise are howling with laughter.

who do want to join in and tickle the feet of?