-Shiu keeps a safe house for emergencies (a shitty apartment) and he lets Toji crash there whenever he wants, or if he's feeling generous, he'll let Toji crash at his actual apartment (which is much nicer)
-He calls Toji (and megumama) pet names in Korean
-Shiu has a kink for men in lingerie, which Toji has absolutely indulged before
-Toji started smoking because of Shiu offering it to him after sex
-Toji still gets flashbacks of living with the Zen'ins and he thinks that Shiu doesn't notice when he comes to him for comfort sex but Shiu is just too polite to say that he knows
-Shiu is divorced because of an affair (Toji), and even though he's definitely in love with him, he won't ever admit it

:)