Jiro and Ma-kun had been friend since they were little. When they were in Junior High Jiro kissed Ma-kun, Ma-kun just ignores it and treated it like it was a joke but they never talked since then. They grew up separately, Jiro now a grown up 21yr. old came back home and Ma-kun is acting as if he's been wanting to see Jiro back again and even invited him to go see the fireworks and then sparks flew the second time around!

(Source: MU)