Remove the vacuum breaker while you're at it, which is typically buried in the rear of a cabinet behind a baffle, and make it a direct connection. Then it will be self draining as long as you do not create a trap in the line.
Not only does that eliminate the chance of the cheap vac breaker sticking and flooding your rig, but they are always mounted higher than the inlet port and create a trap in the line that will hold water.
That said if youre a germophobe or have a code fetish, you can use a seperate vac break on the hose or site connection when using the flush.