I don't what kind of rigs are put together so one can dump without a hose, cleanly, anyway.
Our Itasca motorhome has the end of it's sewer dump line still inside it's enclosed sewer plumbing cabinet. If I ever tried to dump w/o a hose the bottom of the cabinet would be filled with brown stuff. We MUST USE A HOSE to get the sewage away from the end of the sewer dump line and the cabinet it's in.
Boy ..... some OEM's must really cut corners on their construction! Maybe it's just a towables thing ... whereas all motorhomes are set up the way ours is. :h