I was trying to find an older post, but none of my search phrases netted what I was looking for. I was recently out with a girl and she mentioned "this guy she's dating," and none of the things were very positive. I remember a post that talked about how to handle situations like that, if I should talk bad about the guy or encourage a break up. I couldn't remember what the course of attack should be, so I tried to remain neutral. Any tips on where that post might be found, or maybe just a brief refresher?No clue about the post, but my recommendation, assuming that her involvement with the other guy isn't a dealbreaker at this stage, is to simply ignore his existence and make it clear that you have zero interest in discussing him or anyone else interested in her. This is where Deltas and Gammas tend to make their mistake and either a) leap at the chance to sing, dance, and look like the Potentially Better Boyfriend, or b) leap into the Friend Zone by providing a shoulder upon which she can cry. If she brings the other guy up again after the first time, simply raise your eyebrows and say something like "I had no idea you were still hitting that... interesting."
That should produce some hurried denials or justifications, which will provide DS with good information concerning whether he should be bothering with her at all. It sounds to me as if she's been relegated to a horse in the other guy's stable or otherwise demoted, which is why she's simultaneously bad-mouthing him and continuing to see him. DS has to realize that he may be of lower rank than the other guy, which means he has to up her perception of his rank or she's going to prefer part-time other guy to full-time him.
If she tries to bring him up a third time, DS should simply cut contact with her. No warning, no explanation, no drama, and when she comes around looking for attention, he should tell her that he's got better options than wasting time on a flake hung up on someone else. Remember, women are attracted to male action. Cutting off contact with her may be the message she needs to drop the guy. And if not, at least he won't be wasting any more time on her.