I have visited the NordRhein Westfalen region of Germany quite a few times, unlike In the UK, brothels and sex clubs are legal and tolerated by our teutonic brothers.
The NRW region Includes Cologne, Dusseldorf, Dortmund, Essen and the Rhur valley area.
There are two main type of clubs, 1) Fkk and saunaclubs where you pay an all day entrance fee to the club, use of all the facilities Is Included and food and drinks too, you just have to pay the ladies to take them to a room, usually a standard €50=30min €75=60min One of the best fkk's I've been to Is http://samya.de
/ It's In the suburb of Cologne, so unlike other clubs that are out In the sticks, It's easy to get to, and more Importantly It's run well, listens to feedback and attracts many sexy girls, ohh and the bier's free lol.
2) Partytreff's are an all-Inclusive club, you pay a set amount at the door, eg. a three hour ticket or a all day one, and like a fkk you can use the facilities, but also sessions with the ladies are In with the price.
You will usually but not always find the stunnas at the top fkk's, as they can make a lot of money, but to be fair you will find a diamond In the rough at PT's too.
I have used the ISG for good tips and knowledge on the German scene, WSG just hasn't got that many good reports on the fatherland.
The Pauschalclub In Dortmund Is only 5min walk from the arrivals hall at the airport, http://www.pauschalclub.de/dortmund/home
Imaging having that at Luton airport lol, Harem Platinum Is just outside Dusseldorf, It's half of a saunaclub, good reports and facilities, with food cooked to order, http://www.harem-platinum.de
/ It has a sister club north of Cologne. There are many more clubs In and around this region, obviously some better than others.