[Callers] don't do it yet!

This may have been covered before - I'm relatively new to this list and to contra calling (~6 months) but I'm an experienced MWSD caller (18 years). Last weekend I called an open contra dance with a large number of newcomers. Each time I introduced a new call in a walk-thru some of the experienced dancers would "jump the gun" and (begin to) do the call before I could even say "don't do it yet" or "but let me demo (or explain) it first". This was a problem and a bit awkward to have to ask them to "undo" or wait for me just a little bit more. It caused confusion and took up valuable time. In my MWSD world, I have students for months at a time (learning large numbers of calls) and they get used to my style of teaching and introducing something new. I'll say "new call time" to get their attention and get a chance to explain what they will be doing before they do it. Experienced dancers ("angels" in MWSD parlance) know not to jump the gun. I even use a bit of the future tense to indicate that I'm describing an action but not asking them to do it just yet, e.g., "you are going to cast 3/4 and then..." and my students and angels know that this particular construction from me means "DON'T DO IT JUST YET!". But they are "trained" this way since they are in a continuing class setting. How do you handle this in a contra setting. What language or other techniques do you use to indicate that you're not quite yet done talking and you want them to listen just a bit more or perhaps watch a demo from one foursome? I'm thinking something like "In a minute, I'm going to ask you to do a Ladies Chain and what you will be doing is..." (though that's too wordy for my own taste). I think it is important to name the call before you describe the action, as this at least clues in the experienced dancers what they'll be helping on (and it's just good teaching). I've been to a dance where the caller tried to describe a star promenade and butterfly whirl without using those terms and the experienced dancers were confused. But how to keep them from jumping the gun? Any insights appreciated! /Andy Shore http://andyshore.com/ "Men of few words are the best men" . - King Henry the Fifth (Act III, Scene II). "Words, words, words." - Hamlet (Act II, scene ii).