Ijiwaru na Hito

1: A Nasty Person A young man falls in love with his seemingly innocent, cute teacher and somehow they winds up in a sexual relationship. 2: World's End Supernova A naive rich kid's father tells him the world is going to end that night, so he rushes out and begs the senpai he's in love with to have sex with him. 3: Amai Yuuwaku A cute slice-of-life story about two men who're already in an established relationship. 4: Line Shima and Nobunaga have been together for 10 years. Though they surpassed several trials throughout their relationship, why is it that Shima still feels insecure?