My son and his buddies, who will all be going off to college soon, have a friend who always brings his younger girlfriend along for guys' nights, where they play video games, Guitar Hero, etc. She tags along everywhere with him and it's embarrassing for the guys when these two kanoodle in the hot tub and constantly make out on the sofa. They want to ask him not to bring her every time, but they don't want to ruin their friendship with him. Any suggestions on how they can handle this??