Sulli of SM girl group f(x)'s nickname is the 'giant baby', she's been known to behave like a baby despite how she hates being called a baby by others, all throughout her career as an idol but not until recently though. Park Chanyeol, a member of EXO-K, SM's latest idol group, he doesn't treat Sulli like a baby, despite Sulli being younger than her, Chanyeol treats her as a mature adult and as a senior of course. 

Sulli favors to be around Chanyeol the most than her bandmates since she feels like she can be a grown-up with him and not a maknae or a baby. Chanyeol also seem to like being with Sulli cause she always takes him seriously and not some kind of happy-go-lucky guy. Sulli doesn't like being treated like a baby but she does like being a baby BUT only to the given person and out of all the people in this world, Sulli acts like a baby with the one guy who didn't treat her like a baby. 

Nowadays whenever she is with Chanyeol, she always whines like a kid, she becomes so useless that Chanyeol had to do everything for her as if he is her butler, Chanyeol had to do a lot of things for Sulli but she doesn't let Sulli's behavior to ruin their friendship, despite being a baby she still treats him like he is a reliable guy, although his EXO brothers think that Sulli is maybe taking advantage of Chanyeol but he doesn't care what they think. 

A lot of people knows about this weird enslavement of Chanyeol to Sulli, the one who cares for him the most, Yuri is always concerned over Chanyeol's well being, he always pushes himself just to be by Sulli's side. Sulli also sees Yuri as someone who seems to despise her for some unknown reason, she notice how most of the SNSD seniors are kind to her but not Yuri. Sulli wonders to this day why she doesn't seem to like her.

(A/N: I've been an avid EXOshidae fanfic writer, now i'm moving on to f(EXO) but i'll still be writing EXOshidae/O though)