Reinforcing black water discharge pipe slip joint

For the second time in two years, we lost our black water discharge pipe on rough gravel and dirt roads, not from striking obstructions but just shaking loose. The first time, I had my local dealer replace it but this time we recovered the pipe intact on the way home and I've decided to reconnect it myself, stronger than before. The first thing is to use metal strapping that is several gauges thicker, but I'm puzzled how best to reinforce the slip joint at the tank. A 3” rubber coupler at the hardware store is the only thing I've found there that might work, if it can be forced to fit both sides, or rubber sheets I have for mechanical dampening, clamped across the joint.