Never used it. Granted we never have had one in the first place.
I was taught in the old school ways that Sh%$ always rolls downhill. It does that naturally and does not ever need to be helped (pressurized).
Our reality: We have had a couple of accidents when we have been dumping our black tanks over the past 30 years. All of them were a malfunction of assembly, execution or other reasons that the end of the sewer hose did not stay securely connected to the sewer connection at the dump site. Looking back at those unfortunate events, the effort we spent to clean up after our misfortune and the humiliation we caused ourselves - I shudder to think what that mess would have been if the end of that hose was 1.5 inches and under pressure.
I chose to leave gravity and the forces of evil to other opportunities... NOT with the Sewer line.
Steve & Stacy,
Oliver, Ned and Ellie ( Yellow Lab, Red Lab, Border Collie/Boxer)
2015 Seneca 36FK
2007 Toyota FJC - on the trailer