Ptoms, I do not kinow if your TT has a docking station, if you do, it's in there. On my previous unit (A TT) I had a black tank flushing system, it was a white rubber garden hose inlet 4' up on the side of the TT near the dump valve for the black tank. They put a decal nearby warning not use it without having the black tank dump valve open (the bowl would runneth over). Basically, you hook up a garden hose to the inlet and turn it on while dumping. It's a no, no to use your white drinking water hose to do this for safe health reasons. I carry a 10' black hose just for this purpose. I also put a angle fitting on the hose end that hooked to the TT to take the strain off the connection. I never use this black hose for potable (drinking) water.