I would think that it's up to your coworker/his girlfriend to tell him that he needs to straighten up. People like that just make others' uncomfortable and no one will want to come to future parties if they know he's going to be there. If she doesn't have the audacity to tell him to clean up his act, then someone is going to have to throw down the towel and tell him to shut up or get out! If he still can't cut the crap, next time tell the office everyone's welcome to bring their spouses/significant other, EXCEPT her.

I'd be more apt to subject him to public humiliation, but that's just me and I've dealt with too many of those jerks. I'd let him know how unattractive his actions make him look.

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Some people walk in the rain, others just get wet. ~Roger Miller