Did something like this once with a 20 year old Swedish ex in London. I collected her after a night clubbing and told her I wanted her to pick up a guy to bring back with us. First guy she approached freaked out, then she approached a guy waiting for a taxi and spoke to him. He ended up coming back and he and I took turns fucking her for hours. He left around 3am and we never saw him again. Didn't even get his name. Though I did get some videos of him fucking her. Perfect.