Yeah, I think the bottle to walk definitely comes with age and experience. I've done it loads of times. Quite often I used to go to La Maison, see who was working, if I didn't fancy any of them, just say no thanks, and walk round the corner to Wonder Lounge / GFE.
One tip to avoid nerves or embarrassment - remember a name or 2 from their website. So if you don't fancy the girls when you're there, just say "I was hoping to see X" or "what days does X work?". Easy.