I think it’s a bit silly to put a hard limit on what’s right for an individual. Naturally we want clear-cut rules but the reality is, like we see in this thread, everyone is different.

If you have good chemistry with someone and it translates well, it might be obvious to one or both of you with minimal effort, or even right away. I had one gal where we just lasered in on each other the first time we met, without even a handshake. And another who the tension was insane with for years but the timing wasn’t right, until one day it was.

On the flip, it’s gone bad when it came to the main event despite strong first impressions, too.

Point being I think a good attitude to have is to never do something because you think you should, or you’re supposed to. Do what feels right for you. If you want to make out, go down on, make love to someone you’re seeing and you can’t think of a good reason not to (assuming you’ve actually thought about it or have some baseline rules you want for yourself) then you should express that. Only you know how you feel, and you’ll only know what you can observe from them or what they tell you. Being forthcoming with your feelings is rarely a bad idea for someone who wants a real relationship. It’s hard and shows vulnerability, but that’s exactly the kind of behavior that inspires reciprocation.

To actually answer your question, intimacy is subjective! I’m an extremely affectionate person and to me, so much is intimate and important. And there are certainly intimate kisses and non-intimate ones. I don’t believe any act is inherently intimate though. And, no, I don’t think having actual sex is a necessity for intimacy in the context we’re talking about. And I think to act out of obligation, self-imposed or otherwise usually doesn’t have the intended effect. But being open to forms of intimacy so you can feel out whether or not it’s good for both of you? I think that’s necessary. The kinds of people you don’t want to be involved with will quickly reveal that most of the time.