Step one: Land rabies with primary weapon setup
Step two: Do weapon switch. For the rest of the duration of rabies enemies will take the higher damage AND -resists from your switch gear regardless of what weapons u landed rabies with.
Step three: Press walk button, walk away and laugh as smiters flop over without being able to hit you.
Note: The only thing to keep in mind is that the switch trick only amplifies rabies for the remaining duration. If you land rabies then switch right away it will be most effective. If you wait forever to switch then most of the damage is done already at the lower damage/minus resists.