Also.... when you buy an inline filter for your 'city water' connection, it comes with a short hose with a spring on the outside so it is 'flexible' but doesn't kink. When you get a 'spare' you can put that on the backwash connection and leave there. Then connect to that ...when you are 'cleaning' the black tank. It will last a long time... just don't put it back on your 'city water' ... it would not be wise..
The advantage here, is that you only need be 'careful' when making the initial connection with the short extension ... then it will be easier to negotiate the connection...
Peace and Blessings..