[gregarious_introvert]

It can be tricky when you have no knowledge of the subject matter, but a lot depends on whether it's a subject you feel you might like to know more about; I know this is easier said than done, as many people may not feel confident enough to do so, but my advice would be to admit your ignorance and use the opportunity to ask questions. Some of us don't like to admit that we don't know about a subject (especially if it's one which seems to be prevalent in popular culture) and will try to bluff our way through, but I believe it's better to be honest. You never know, you might just find it more interesting than you realised - and people do like being asked about their interests.

Banter can walk a fine line between good-natured ribbing and hurtful insults; I've worked in a few places where banter seemed to be the main form of communication and/or bonding so I've got used to it over the years. It can be difficult for a lot of people to "give as good as you get", or to speak up if you think a line has been crossed. I've rarely had to say something like "I think that's bit below the belt, pull your head in" but I would if I had to - mostly, though, if I can't respond in kind, I'll deprecate myself to the point where the insults become meaningless (they do stop if they see they can't get to you - well, most of the time!).

I'm not really sure what to say about the bragging and the sarcastic references; I would probably suggest that they shouldn't comment about someone unless they're happy to repeat the same thing to their face, or they're present to defend themselves. Hollowone, you mention that you feared being publicly humiliated, but I'm hoping that wasn't the case? We all know that it's the person doing the bragging who is showing themselves in an unfavourable light, but that doesn't detract from the humiliation we feel when they turn their attention to us - but a comment along the lines of "Maybe I'm a little more selective than you" often works.

The problem with most of these situations is that, a lot of the time, we are so consumed by our anxieties that we can't think clearly; this is why we will go away and ruminate on the things we wish we had said, when it's far too late to say them. One tactic might be to imagine what might be said in advance and prepare what seems an off-the cuff quip beforehand, but even then we may not have the ability to recall it. Ultimately, each situation needs to be judged on its merits, but if we feel as if the only reason for our presence is to be ridiculed, then maybe the relationship is a toxic one and we would be better cutting that person from our lives?