Sing Aine Kleine

"Back then, we were alone in the world."
One sleepless night, a young insomniac man entered an online chatroom that was no longer in operation. A person calling himself "Yoh" appears in the chatroom where no one is supposed to be. When he asks the young man what his name is, he introduces himself as "Aoi," and a conversation begins. As they deepen their relationship, Aoi confides in him that he has insomnia..."Well, why don't you try sleeping with me?" Yoh's unexpected proposal makes Aoi...
A slightly painful, but true, bromance between two lonely young men.

(Source: Shusuisha, translated)