Oral threesome?

I love My bf very much. We're both 22 and have been dating a year and a couple of months now. Sex is absolutely amazing but being the amazing gf that I am I promised him one of his fantasies... To an extent of course lol. So instead of a 3 some( not happening especially since I'm his first) I agreed to do oral sex at the same time for him with another girl but I have no idea how we're going to find someone. He keeps asking me to find someone to do it but idk how to go about that. I would feel weird if I knew the person already. I feel like I should just wait and see if I ever meet anyone but then again that could never happen either lol. I'm just looking for some opinions/ advice on this. Thanks 💗