Well, this is similar to the previous post, 夢オチ[yumeochi] though this is not a way to conclude the story as a matter of fact. So 朝[asa] means morning, and チュン[chun] means chirm. I don’t think this is common all over the world, but in Japan we usually hear spallows chirming in the morning…so what about that??
Mostly, 朝チュン is a way to skip a sex scene in TV drama series, manga, anime or whatever. Unless it’s porn, any obscene images should not be shown in Japan. So for example, in a sope opera, when a boy and a girl are having a nice dinner in the room, they feel like having a sex. However, it mustn’t be shown on TV, right? So next moment, a scene changes rapidly! Maybe what we would probably see next, is the couple sleeping on the bed so peacefully in the next morning. And some spallows are chirming…You know what I mean? They must have done it even though it didn’t show us. This is 朝チュン.
I think 朝チュン is used for many years especially in soap operas, shoujo manga or something like that. Having said that, this might make people who really want porn things disappointed or upset somehow. Yes of course, the most important part is missing, right!?