Football_Lover, I followed everything you said... until the belt/loops. Playing with your belt means you're thinking about sex?!
Maybe it means he ate too much for lunch. Or that he's lost weight and can't tighten his belt enough?
I remember having a crush on a guy who was (thankfully) in a couple classes with me. In fact, he only lived a couple blocks away. I'd time things just right so I'd walk to our first class together and sit where I can get a good view of him.
However, it was a good frew years before I came out, so it's not like I was going to approach him.
About 7 years later I ran into him in Saugatuck (he was hitting on a friend). He wasn't out in our undergrad days and of course had no idea I existed (maybe a better strategy is to sit where he can see you). I didn't feel too bad about it, especially given that he'd chunked up quite a bit.
There's nothing like a finely tuned gaydar, but GSP can go along way, too. (: