Tsubomi is a member of the swimming club and practices every day. Natsume, a beautiful teacher and advisor to the swimming club, is aiming for such a bud. Natsume uses her position as a teacher to sexually harass Tsubomi. Thinking that Tsubomi is serious about swimming, she accepts it. Tsubomi, who is straightforward, unconsciously reacts to Natsume's disgusting tongue technique and learns lesbian orgasm. As it is, will it fall into another gentle lesbian intercourse with a man?