What does Back Seat Syndrome mean?

Back Seat Syndrome meaning in Urban Dictionary

The inquisitive phenomena through which males taking a trip in the back of large jostling automobiles (busses, vans, ect) have a tendency to attain spontaneous erection due initially into jostling for the car then secondarily to the jostling of their own lumber against their legs and/or pants. This hard-on could often be relieved only by extrication from the back-seat.