Really? I think Matty has always been the ‘flirtier’ one towards Courteney. If you take that Rolling Stone photoshoot you can actually watch him touching her and being totally flirty with her. And also he always said stuff like ‘I was checking out Courteney’, ‘I get to kiss her a lot which is awesome’, ‘She’s pretty hot’ etc etc.
As for CC, I guess maybe she just didn’t really act on it cos she knows how goofy he is? Idk, I’m not the flirty type of person either so I would just blush and run away (lol).