I'm in Berlin, so it might not apply to you, but I find access is pretty good. I haven't seen much evidence of a "scene", in terms of
vaping bars and such, but there are about a dozen vape shops around Berlin. Most of them tend to be rather small with a limited selection. Many people order from german online shops, it's easy to pay with bank transfer, and delivery is fast for around 5 euros. You won't find all the American brands, but many of them, eg. Halo etc., are carried by a few shops. As far as I know it's very difficult to personally import things from outside the EU, but there are also many EU manufacturers as alternatives.
As far as where to vape, just use common
sense I guess, and try to be polite. I don't expect that I have the "right" to vape anywhere other than in designated smoking-allowed bars, but I don't like to go to those. I wouldn't vape on the subway, but I might on the platform. I wouldn't normally vape in a restaurant where people are eating, but I might in a non-smoking cafe/bar, depending on how it feels, how crowded it is, and so on. It was only a few years ago that smoking was allowed pretty much everywhere, so nobody's going to freak out about you
vaping, the worst is they'll say it's not allowed.
Best place for more info:
Dampfertreff - Das e-Zigarette Forum, Infos zu e-Zigaretten und e-Liquids
Hope you have a good flight!
