you're body language will tell all! you can be friendly, as a friend, you can be friendly, as a flirt, you can be friendly, as merely not being rude when you'd rather....you can always continue you're talks and wait for him to make the first invitation beyond them. That first personal conversation about your relationship status can be a casually put announcement on how it is and where you want it to be without being abrupt, blunt, or awkward. if you like being single..."i'm single haha. I like it, it's nice to have time to myself...or whatever", if you'd like to date him, "i'm single (cute smile), I can't seem to find any good guys. (light hinting manner). whatever you do, don't be overbearing in whatever manner you're trying to get across. Natural, relaxed, comfortable behavior. and I would definitely let the conversations continue as they are until you have decided what you want.