He hesitates a bit, not because of the mistletoe creeping in from above- he doesn't notice that, but because he's deciding how much he'd like to show Tseng about himself. He doesn't usually mind about these things, but even Demyx realizes that essentially stalking people kissing and taking notes about it is a bit off.

Even so, after a bit, he reaches into his pocket to take out the familiar-to-many index cards. Feel special, Tseng. "Well, some people get pretty angry, and then there's yelling. Some people get sorta happy, or don't look at each other afterwards, and most of them get all red in the face. A lot of people also just stare at each other when it's over, and start waving their arms all around."