The 10 Best Positions for Having Sex in a Car Somewhere between standard missionary and the lap dance is the squat thrust, a way of. Missionary: This is the most comfortable position to have sex in a car. Make sure you try this in the back seat though. It will give you a little more. Here is a list of car -friendly sex positions for you to get it on in the backseat. Positions include missionary, girl on top, reverse straddle and doggy.