wanna watch your girlfriend get gangbanged

You have a fantasy about watching your girl with other guys. But you are only guy she has ever been with and she is very innocent proper young girl. She has only done missionary with you refuses to try other positions and almost left you when you mentioned anal. She has given you a blowjob twice but never got into it. You decide to get her really wasted and have her gangbanged. But you got to figure out who you want to do it.