MWO's and CWO's are addressed as SIR, or by thier appointment. i.e.CSM or RSM, BSM.
In the Air Force, they are sometimes referred to by Mister as a sign of respect, or by their designator, FE would be FLIGHT and LOADIE would be the loadmaster. ( I'm not sure if a high rank Traffic Tech would be designated a loadmaster)
You would call all of them SIR or MISTER if you meet them on the street.
I'm VERY sure that if you ever addressed any of them incorrectly, you will be quickly corrected!
"what does a Cpl do when a MGen wants to use the only urinal in the room...and your standing there and what do you say as he is standing waiting"
Hmm, I'd finish my business and flush, wash my hands and say good day sir, then walk out...simple??
Urinal Etiquette stipulates that very few words and maybe only a nod are accepted means of communication in or near the urinal. Under no circumstances is it acceptable to depress your line of sight more than 1 degree below level. (Yes, most General Officers are men with the same equipment you have, so don't bother looking and they put their pants on one leg at a time) So Stop freaking out. :