It's been just over 10 years since I've visited the FKK clubs in Germany...I've had some great experiences there and some not-so-great ones. The recommended procedure is to get a seat where you can watch the girls going and returning from the rooms....watch the traffic for at least an hour before you make your choice. If the girl and guy return quickly and separately = not a good sign. OTOH if a girl and guy are gone for awhile and they hug & kiss when they return = good sign. If a girl is constantly going to the room with different guys = she's popular, which then infers she is offering excellent service, the word gets around among the regulars who's hot. For these popular girls, try to snag her as she returns to the club before some other guy does. As previously mentioned, some of the girls speak decent English, I like the ones that want to converse with you in order to improve their English skills = good attitude, she wants to improve herself to be more appealing to English-speaking customers. On my last trip I recall several examples.....met a stunning model-quality 10+ Romanian girl that spoke no English, another girl offered to translate...big head won on that one, I decided to pass. Then I met a girl who spoke good English, but when we got to the room, wanted to change the deal to "100 euro suck & fuk" which at the time was the standard non FKK indy rate....to my regret the little head won and I went ahead, needless to say it wasn't an outstanding session.
A friend of mine recently returned from Germany, he reported that he had a great time at Samya FKK in Cologne (Köln) and at Erlebniswohnung (sex party) in Berlin. At Erlebniswohnung you pay one flat rate for all-day entry and you can have as many girls as you want, he said the girls change in 2-hour shifts. Both these places have good websites, just google them.