Kissing someone with no real purpose?

Just something I have been wondering about, would you kiss someone just because you wanted to, even if you had no intentions of going further or developing a relationship.

I'm attracted to a girl and I know that she somewhat has feelings for me... she recently got mad at me, because she thought I had a crush on another friend and that friend said that I was hers and only hers. I also know that my close friend flirts with this girl a lot and that this girl has told her room mate that it bothers her when my friend does it..

Then.. the girls roommate told my friend that she should back off and that its okay if I do it because the girl actually has feelings for me. Me and said girl flirt, cuddle, hug a lot, hold hands and she sometimes loops her arm through mine or puts her hand on my leg.

The only thing we really haven't done is kiss, and there have been times where I have really, really just wanted to go for it. Sometimes I feel like I can tell that she wants it too, recently we were laying down together where we were facing each other. There are a lot of perfect times where I could just do it.

Having said all of this, I also know that she likes someone else, a guy who has had a crush on her for years and I have a feeling that they will begin dating soon. Now I just want to kiss her while she's still single, because I don't know how long she will be unavailable for again.