I had a buddy of mine call me last night for help on a situation... he had been sarging a couple broads, and to counter a block from one of the girls(the block was something to the tune of "if you're gonna try to pick up girls, you should stop acting like an asshole" which in actuality isn't necessarily a great block), he told her "to not amuse herself, he had a gf." Many would think that he killed off his chances with both, but I've seen guys dig themselves into much bigger holes. So he asks me how to handle the situation if one of the girls he sees asks about the gf.
First I want to address a different route he could have taken in the situations that led up to now.
I believe that whenever you sarge, you never lie (even if it is unintentional... I've done it many times in the past when I was a huge AFC to try to save myself and it really becomes a big mess). You be upfront with a broad and she never can call you out on anything. Now I understand the "I have a girlfriend, don't flatter yourself" line is a common reaction just because it's an easy way of killing off the pick up vibe, but you might set yourself up in a sticky situation(and not in a good way... o jeez bad pun) that would have you snowballing into tons of resistance, or worse, the friends zone.
So let's get to MM's hoop theory:
You have three options when presented with a question, shit test, qualifying, etc.
You can either GRAB the hoop(and make her jump through it)
PUT UP another hoop(to lead her in a different direction)
or SHUT UP (kill off the test completely)
Another take on shit tests or questions is something I picked up from David D, which is to never give a girl a straight answer, or make her work for it. It's basically hoop theory in broader terms.
So let's use some examples:
If your going to try to pick up girls, you should probably stop acting like such an asshole... (this really means, I'm interested in you, I still don't know why, maybe I should kick you down a couple pegs so I can stop being attracted because I'm not supposed to be interested in guys like you)
GRAB - Well if you're trying to meet new people, you should probably stop being so rude. (and move on before she even gives a response, because it gives her a chance to think)
The Grab is used to keep the context of the question the same, just reversing the target.
PUT UP - So tell me the story behind that scar...
The Put Up is used to change or divert attention to something else, moving the interaction in a different direction.
SHUT UP - *silence and a blank stare*
The Shut Up is used to create awkward tension, and is briliant if handled with the right body language. It is extremely important that you hold your ground on this, because this is an instant call of attention to your inner confidence. If there is a hint of you being self conscious, you will have lost rapport and respect.
All three responses say that you don't need her to qualify how great you actually are, and that you have the ability to shrug small stuff off.
Now back to his situation now:
So what happened to your girlfriend? (she really is asking you if flirting with her is your way of rebounding off of or hurting your girlfriend, which in turn if the new girl were to pursue, would she be getting the same drama?)
GRAB - O so you're trying to figure out what not to do so we can make this last longer... (take that hoop and turn it around on her)
PUT UP - (kudos to my buddy for coming up with this one on his own, thru facebook) Hey what happened to your engagement? (the context is that the engagement was one of those girly "I'm engaged to my bff" bullshits)
SHUT UP - *when she presents you with this question, act withdrawn...hold silence... as if she brought up a sore subject, in which you then talk about how things didn't work out while staying positive* (this will show that you cared enough about the broad beforehand to respect her by not bashing her behind her back)
All three should prove to the girl that you are not looking to be vengeful or hurtful towards women, or that it is a subject that was important to you once in life but this isn't the time or place to talk about it. You are here to be playful and fun. And if she really wants to know the deal, then she is going to have to work for it by really pursuing the answer.
Reading into the subtext of the question is important(broads say and mean different things, and if you're not blind you should have realized that by now).
Ultimately you have the power to control where conversations are going. So make them pleasureable for you.