When Kristy is involved, it might be because Kristy is a person with almost no intime zone, she cuddles with everyone.
To me, that stroaking, cuddling and even kissing is not particularly interesting, I do not know why, maybe because I feel it is just teasing, or because I know they are friends. I love to see Nina & Kira do the exact same thing, but that seems more real to me, more like an expression of love.