Help me with a girl please?

So I have been hanging out with this girl for awhile and she came over with a couple of friends but my friends left and she stayed and we watched a movie. I'm trying wait for a moment to go in for the kiss( we're sharing a blanket and shes like snuggled up with me so it's not like she's not interested) but I just kept waiting for the right time and it never came so when should I do it or what should I do to help lead up to it?