I go out and see some guys who are close with women all the time but they are not be necessarily couples as far as I can tell. Yesterday I was with a group of new friends. I was trying to gauge whether the girls in that group were with the guys as its not always obvious. There was a girl who seemed interested in me but for a short second rested her head on another guys shoulder. But nothing more. And after, they parted ways, no kiss, nothing. So they were unlikely a couple. There was another friend who was talking very closely with a girl. After, they had their arms around each other for a bit, but again nothing about them shouts a couple. No kiss or romantic looks. Again they parted ways after. In case you think I'm just guessing around, there were two occasions I asked a girl if the guy she seemed very close with earlier her boyfriend and she said "no". It's not a question I'm comfortable asking. These were exceptions!

My question is twofold really. How do you tell whether two people, who just happen to be talking but are quite close, are a couple? Should you care when deciding to approach her or not? Second, just how close and touchy and feely can a non-couple be? Certainly, the ones I've seen are a lot more than what I have been during flirting. It makes me wonder if I could go further, more hugs, arms around her waist etc. Maybe this would take escalation further and make it easier. Except I have always been far more respectful/Conservative when it comes to physical contact. I'm doing the sort of Kino you guys talk about here. The examples I'm talking here go far beyond that, almost like a couple just without the kiss. I wouldnt want to come across as pervy or creepy.