Thats what I do. I always hold a little rpm to it before I bump the switch. But before I do that, I always bump the switch before I even turn the bottle on to make sure I got fuel coming through. Ill do that a couple times and actually almost choke the motor off. If it doesnt try to choke the motor off from having to much fuel, you know its not getting fuel, and thats bad LOL. Then I turn the bottle on, rev it up a little, and bump the switch one time. If it revs real fast, I know its ready.
At home before I leave for the track, Ill arm the system and pull the nitrous line out of the nozzle (making sure to take the jet off) and bump the switch to make sure its working. But if you do this, make sure you got a good hold of the line, cause it will be violent LOL. Could do the same with the fuel line, but it wont be violent. Just make sure its got a good steady stream.