I think Cullen could be read as flirty in that invite to play. But it almost just seemed like he was being super friendly... like he reeeaally wants to make friends. Sorta, puppy dog like. Which is just... honestly, flabbergasting. He was always so formal with Hawke, even when he was friendly. But this?? Wow. Boy is opening up big time. WAY more than I expected. Still collating.
Probably because he never really interacted with Hawke and/or the Warden outside of Official Templar Business; even with Amell/Surana, he's a templar first. But he's not a templar anymore, and he has to see and work with the Inquisitor day in and out. Might as well be friendly.
I have to say, I was worried that he was going to be the more formal and stern Cullen of DA2, which would have frightened the hell out of my poor Lavellan at first. It's great knowing that he'll be friendly.