My ex and I had a LTR and then a LDR cause of college. After one year, these arses used BFD on me and it worked way too well. This was before I knew pua/bfd stuff existed so I didn't know how to handle it. Well now she's been going out with one of them for a while, but she's home for summer break so I'm pretty sure it's going to be a LDR for a while. I asked her out to get lunch but she said she doesn't want to worry her bf. How do I counter/get her to hang out? Also, any advice on how to steal her back?

You actually want her back? As in someone's sloppy seconds? Run the same techniques he used on you. Put her in FZ then escalate. Being her back to the past, like remember the times we used to have?

Her: I don't think I should I don't want to worry my boyfriend

You: woah don't be so serious. I just wanted a drink and a catchup.

Aka make it weirder to not do it then to just do it.

Then friendzone he then escalate then fuck. Not hard.

Escalating is even easier than with a stranger. You've already got familiarity where things like touch were normal. You can escalate and she'll be less likely to be thinking wait a minute, what's going on. It's all just stuff you used to do, it won't seem unusual. As said above, make not being familiar seem weird. The more normal she starts seeing stuff then escalating will just feel like normal too. By the time she starts questioning it you should have rebuilt attraction and comfort. I did it recently, you can get away with stuff far quicker than you can with a stranger.