I second get a room. Even if just for a few hours. You'll both be more comfortable and the plus is she won't think of you as a cheapskate

Unless you are driving a Kia Grand Carnival and have all the back seats cleared. Everyone will need to do some form of yoga poses to fit in any normal car... Plus everyone can spot the car bouncing up and down even with newspaper, tissue or fog on your window... In this day and age, dun be surprised you might get to review your performance when someone post their video of you later