How should I greet him (hug, kiss, etc)?

I've been on two dates with this guy now, we met on tinder. He kissed me twice on the second date last weekend. We had an amazing time.
So, I always see him at the same time on Thursdays eating lunch with friends at the college we go to, but I've never approached him there (I'm super shy). We actually met for the first time there on accident, but he was alone that time and he noticed me and said hello.
Anyways, I feel like since we've been on two dates I should approach him if I see him on Thursday.. should I? And like, how do I act? Can I kiss him? I want to still seem interested, but I don't want it to be weird in front of his friends?
How should I greet him (hug, kiss, etc)?
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