When you go in for a cold approach, do you know exactly what you're going to say or do you just wing it?

For people who approach women frequently in bars, etc. do you rehearse what you are going to say before you go up, or do you just approach without thinking about it and improvise from the get-go?

By this, I mean, do you just sort of internalize the "game" from prior practice and not have to think about it, or do you have to go over it again in your head before any new approach? Basically, what does your "zone" look like?