It may help to keep in mind that in some circles; for both practical and traditional reasons, one doesn't even resort to such things when amongst the "uninitiated" (including full on 24/7 TPE relationships as well).
Additionally....some "tasks" simply cannot be completed all the time. Heck some tasks aren't even designed to be able to be completed at all (something both of you should be well aware of) and if he really has a preference and all...why doesn't he come up with it himself? Who knows...
Either way I wouldnt loose my cookies over not being able to "guess" what he may allready have chosen in his head if anything.
Some possible things that may or may not help but which dont draw attention to one's lifestyle or include the unintiated:
HMFIC (head muther fraker in charge)
Boss man
Boss
Papa
Daddy
My Lord
High Farook
Honey
Sugar
Mr (whatever his last name is)
Captain
Generalissimo