Chitose Is in the Ramune Bottle, Vol. 6 (manga)

In order to deal with a potential stalker, Saku and Yuzuki decide to fake date each other. Soon, rumors are blowing up about the latest good-looking couple in town, and things go way beyond expectations! Yan High's delinquents come after them, a lovelorn Tomoya Naruse seeks Saku out for advice, and just as Saku is having a friendly conversation with Asuka Nishino, Yuzuki butts in and asks-"What is the deal between you two, anyway?!"