Elec. cable scuffing tailgate. Help

I am on my first long distance trip in my new Toyota Tundra CrewMax. The truck pulls like a charm. In my old truck I had the electrical plug installed in the bed of the truck. I decided to use the plug below the bumper to avoid splicing into the electrical system. The wire hangs over the back of the tailgate. I am noticing that the wire is rubbing against the back of the tailgate and scuffing the paint.
Do they make something to suspend the wire farther back so it doesn't touch the tailgate? Has anybody come up with a good solution to this problem?
Thanks in advance.