If one buys a corner fence post, it will have openings on two sides---place one opening facing front and the other opening downwards. Drainage and circulation! I've made 4 of these and all worked well-50,000 miles well. They all contain 2 long sections, the screw in dump thingy, the elbow, and heavy rubber gloves.
I mounted all on top of the metal sewer hose holder with whatever was available for spacers to keep the plastic off the metal.
One end has a cap screwed on, and the other end (in my cheap thinking)has the cap held on by two pieces of coat hanger stuck through holes in the cap and sewer pipe. Never had a problem.
Even might match the color of your trailer in some cases.
