It worked for me. That's what I'd do. This other guy "evergonitenitenigga" clearly doesn't get it. Just because you're targeting someone you're friends with doesn't mean you can't also talk to other women too. If you have a problem with what they call "oneitis" and it's preventing you from getting laid otherwise then you should forget about it and work on yourself further.
I was fucking around with my best friend's (the one in the post) friend she met in college right when this happened. Seduced her at a party the friend in question threw and had her making out with me within probably 45 minutes. Just because you target a friend of yours doesn't mean you have oneitis or no game.
I seduced my friend within 15 minutes of conversation in a dark room using what I posted. Honestly it's either hit or miss - no matter which way you do it. But I think this way is better than flat out telling her you want to hook up.
Conclusion/TL;DR: Yes, personally I would go with what I outlined here. That other guy is being a total asshole. Just keep in mind you could screw up a good friendship if you're not clear when you hook up that you don't want it to change things between you. If she gets the idea that you want a relationship and feels like you mislead her then you're going to have to use your own ideas to combat that because it's a case-by-case basis on how to deal with it. I dealt with mine you can deal with yours. If the girl is mature enough she'll get it anyway. Mine did but it's still something you should talk about. Keep in mind my friend had a boyfriend when this worked too, if yours has someone she's seeing just ask her how she knows he's right for her, and go into what she likes in general about men she's attracted to, get her to qualify you like I said, and move in with the seductive questioning I laid out. That's what I did to her, I pretty much got her to disqualify her boyfriend using questions that challenge the belief; "how do you know he's right for you"; 'oh i don't know yet', "what specifically do you like about someone when you find yourself really attracted to them", etc. then show yourself in through that door. It's important to say, "I'M CURIOUS... how do you know this guy is someone you really like, can you imagine yourself spending the rest of your life with him?" they'll probably say no or "I don't know" and then he's temporarily disqualified.
Best to completely leave the other guy out of the picture though unless you feel like you're in a position where you can disqualify him. PM me if you need info on how to do that. I have some things you can do. For example, something I say in approaches when the girl says she's taken/has a bf is "Oh, that's great, I bet he treats you well, is always there for you, answers his phone all the time, makes you dinner [list a bunch of AFC shit that women think they want and you know isn't really happening].. and you wouldn't possibly be in a relationship because YOU'RE WAITING FOR SOMEONE BETTER, to come along. I totally understand because my best friend has a boyfriend too, what do you like about him?" -- then compltely change topic from bf while setting the vibe that she knows I'm interested in who she is and not getting in her pants (which is 50% true) and get him out of the picture ASAP.