The Tyrant Falls in Love/Tear Jerker


 * Volume 6: After Tomoe and Kurokawa announce their relationship for the first time, who accepts them fairly readily, Morinaga slips off in the commotion to be alone. Souichi finds him crying in the bathroom, because understanding only threw into relief how Morinaga's  rejected him after they found out he was gay,  whom he's not even on speaking terms with anymore. Though he otherwise tends not to make a big deal of it, it's obvious in this moment just how much he cares, and it's hard to resist crying a little with him in sympathy.
 * Chapter 9 of Volume 7. Period.