The first part of their kiss is so intense and full of lust. I mean honestly, Callie is holding on to Brandon like he is going to be torn away from her at any second. After that whole intense kissing Callie just starts to loosen up I bet she’s thinking “woah this is really happening, I guess I can be happy.” (or maybe she’s not thinking anything because she gets to kiss the hottest and sweetest boy ever.) She’s smiling into the kiss because it’s real. It isn’t a fantasy, she’s kissing him and he is kissing back. They are kissing each other like their lives depended on it, and if that’s not hot I don’t know what is.