not certain how we managed it, me at 6'4 in the drivers seat of my 1 series, in the parking lot of the Toronto airport.
was a mix of dread for being caught by people wandering by, and extreme satisfaction after being "teased" for an hour while driving there.
amazingly every time i've done it in more secluded areas, i've always been caught. (oldsmobile or WRX back in the day)
and have definitely succeeded at drive in movies on multiple occasions. (jeep cherokee, WRX, Oldsmobile, Hyundai)
I have found that with my height, it can be beneficial to open windows and stuck appendages out to provide more space for manoeuvring.
another trick, similar to article, move passenger seat all the way forward with the seat tilted forward, and kneel on the rear floor with your lady friend sitting on the back seat facing you, very effective.