Does trailer connector need to be in pick up box

I prefer the in-bed. I had one installed after a couple of problems with plugging it in to the bumper outlet. It dragged on the road and shorted, so I shortened the lead. Then it got caught on the truck during a tight turn and bent the pins when it pulled out. If I keep it plugged into the bed outlet it seems to eliminate the problems. Give me time, though. I'm sure I can tear something up with it plugged in this way, too.