I Wanna Do Bad Things with You manga volume 5 features story and art by Yutaka.

Fuji and Mamori finally manage to beat Koichi's test scores! As a reward for all their hard work, Fuji promises to take Mamori to the summer festival. But she can only go on one condition - she has to wear a yukata! While the pair savors the sweet taste of victory, Kei and Koichi hatch their own secret plan that may ruin all of Fuji and Mamori's hard work…