I think there is such a thing as "getting too comfortable with the people you work with".

My boss came over and wanted to show me how to do a new process. We start going through the steps and a question arises. I then IM my team lead, because he's the one who would know the answer, and all I get back from him is sarcastic comments and profanity (he doesn't know my boss is sitting at my comp with me). So I keep trying to get him to be serious, and he just keeps his mouth (well, fingers) going. (He is remote - not in our bldg). I want so badly to shut him up because what if he says something about my boss while she is sitting there? Not that he does that, but at the pace he's going, it no longer would surprise me.

There should be some sort of code to hint to your team to STFU and give a fucking answer when one is needed. Sort of like what kids do to hint that a parent is in the room, but for work?