Went to a social meet up for girls birthday. What should I have done?

So I'll keep this short. I want to know what I do in this kind of a situation.

Girl who works at the gym and I start talking. I suggest meeting up on a Tuesday. She then tells me it's her birthday and doesn't have plans.

Later in the week she tells me that she decided to have a get together at her house with some friends. She invites me and tells me I can bring some friends. I bring 3 people 2 guys and a girl.

We get to her place. Long story short. To make it less boring we brought cards against humanity. I sit on a couch and the girl sits in a chair to the right of me. My friend will call him D sits on another couch next to her.

Through out the night. I notice her getting touchy with my fiend D (poking, slapping his leg, putting her leg under his.) at this point. Now mind you D isn't doing anything physical back. See just has the tingles for my friend. I am not really able to do anything as I'm sitting on the other side of the room.

So I'm not really annoyed by it. I try to ignore it and not let it bother me. Eventually my friend M calls the night. I'm leaving with them and she asks me why I'm leaving. I tell her I drove with them. She walks us to our car. At this point I'm not really interested in escalating with her. I give her a hug and tell her goodbye. I can tell she was looking for more. I wasn't willing to do it anything with her after her being all over my friend.

I also couldn't tell if she just came out to get something from D. He had no interest in her and walked away.

Edit: Definitely have a lot of work to do in changing my mindset. I'm glad you guys helped me see the beta in this post.