I think it's best in these situations to be cautious but try to be yourself, too.
You're a smart enough guy to understand the kinds of things you shouldn't say on an open forum, but other than that, I think you need to just relax. Most of the people on here seem nice enough, some of us are students or teachers, too. We might even appreciate the things you have to say, or your humour.
You never know until you put yourself out there and try.