Okay, so I've seen some people say that it's twincest; I'm just curious as to how many believe that.

This is a good question! I would probably have thought of asking it too.

A lot of people believe they are twincest; Because of the way they interact, hold hands and share a milkshake. Some people even confess that they are twins and don't do any of that and think it's "crossing the line" but had people considered thinking out of the box a little bit? Cheryl and Jason are not you, their situation and life is not the same as yours, as Cheryl's actress explain perfectly, Jason was pretty much Cheryl's brother, father, friend, guardian, the one who takes care of her and even her mother all at the same time, Cheryl has no one else in her life to take care of her, so they have a relationship that people don't understand, because they can't relate to Cheryl's life.

Because that's what it is! :)