Guy's Behavior

What does putting your arm around someone you've been friends with for years mean?

I have been friends with this guy for MANY years now and we have recently gotten a whole lot closer in this past year. We have begun texting pretty much everyday throughout the day this past summer but not like 24/7 constant back and forth. So we have also begun hanging out a lot more. We have gone thrifting, out to eat, gone to the movies. Normal bestie activities. Recently he started paying for some of my things when we have gone out which I found odd since we would usually always split it or pay for our own things. I didn't start thinking much of it until around 2 weeks ago. We hung out before he went on a trip, and we were sitting in his car because there is nowhere to go at night in my boring town. While we were staring at his phone he all of a sudden put his arm around me and kept it there for quite some time. It is important to note that we are close, in the past like middle school, not anytime recent we would hold hands for no reason. I am now going to be a sophomore in college. So yeah, not anytime recent since that happened. So the night he came back from his trip ( like 11 pm) he asked to hangout again. Once again we sat in his car but I exited to go sit on a park bench (very spacious). This time there were multiple cases where he attempted to put his arm around me but I would always move. Well eventually we were joking around and I grabbed his arm to check it and he put his arm around me where it stayed for basically the rest of the night until we left. I am very confused wondering if he possibly likes me. FYI He does not put his arm around any of our other friends. Sidenote: I don't know if this is important or not but he was drinking with his guy friends and called me one night and one of his drunk friends started shouting across the room saying my friend had the fattest crush on me and thought I was really pretty, but I took it as a complete joke (this was maybe 2 months ago). Like his friend was wasted so I don't now if to believe him in that state.

Updates
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Forgot to add this, but it is the way in which it happens that makes me question it. Usually if I or one of my friends are gonna do this we will go right ahead and just do it no beating around the bush. He tries to do it very subtly and definitely feels as if he is working up the courage. I may be wrong here though. As we sat in the park he had his arm like leaned on the top of the bench and kept glancing back as if debating if he should or not or at least that is what I think.
What does putting your arm around someone you've been friends with for years mean?
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