Ok here's how it went, my mate uses game aswell and he was telling me he wants a threesome before he leaves Australia. Anyway we said no problem and went out with one of his presarged girls.
Tactics he used saying to her were.

One regret me and my ex had was we never had a threesome, once we were together for over a month we liked each other too much so didn't want anyone else involved. I don't want to make the same mistake with you..

Fluff
fluff
fluff

they come to a bar I'm in with a few girls/guys he tells me to Sarge her for 30 mins or so

so off I go got a good reaction.. I ended up kissclosing her when we were alone. Then just straight up phase shifted and went back to the group.
Few more negs through the night and a little chat.

Just walked out together and said my mate owns a nightclub over there come in for a drink. The 3 of us that is. Go in get massive social proof

then just say let's get a hotel room to her.. She's gagging for it!

Called the next day saying she wants it again.

Someone else can try this let me know how it goes on

For me, that is the 'wrong' kind of threesome haha, but if others like it they could try your plan even though its pretty vague and not every girl will do it with 2 guys.