A person who, while present the entire time, when called upon appears to have no idea what is going on as though they've just arrived.
"What's up with Shawn?"
"I don't get it. He's been here the whole time and has no idea what's going on".
"He appears to be stuck in a state of constantly arriving".
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi