Thank you very much.

I'm glad that you find me helpful. I only wish that there were more areas of the forum where I could help out.
Yeah, it sounds like he's serious. If he wasn't, I doubt that he would make any comments at all. See, when I'm around guys that I like, I would err on the side of caution and hold in those impulses for fear of making things awkward, but I could see how an ESTJ in a certain situation (or, more accurately, a certain mood) would do something like that. I think, because of being J, we have a need for total control over a situation, and when you open yourself up completely, you can't safely predict what will happen as a result, and a lot is at stake. Whereas you INTPs are better at improvising, and taking risks.
Was your bolded statement a question? If so, I'd suggest making an equally over-the-top-flirtatious comment back at him - that is, if you like him. If you don't, then maybe you should just be direct and talk to him about it (in private), saying that you don't like him in that way. That would most likely be awkward, but it would bring some closure, which is always a good thing.