Up front, I am not a prolific hobbyist. But I find the good ones, usually.
Of note, the FKK Sauna Club system, which is famous for being able to get a guy legal P4P for €50/HH, has been pointed to by fellow goers as a trafficking location, so one should be aware of the potential problems, especially legal. I've read that so-called "pimp boyfriends" can be seen in these clubs posing as hobbyists/johns. Also, the preponderance of Romanians and Romania's being a major trafficking location and source come into play.Most FKK Sauna Clubs will have a free cafeteria and free drinks including beer on tap, coffee, soft drinks. Anything like hard liquor is extra. The condom law from July 2017 hasn't killed the BBBJ (or FO in German), just made it more costly in some circumstances. AUGUST is usually a down month as that's when lots of the girls, especially the Romanians, go on vacation.
German FKK/Sauna Clubs I've been to:
FKK Palace is a short walk from Frankfurt Industriehof Ubahn station and coincidentally near a German Military barracks (I think a recruiting hqs - you can't make this up). I've been a few times the last decade. Mostly Romanians, but an occasional German and the Ukrainians are coming now, which guys will like because they're hungry and hold the line on prices. Ironically, you may find more "shark-like" behavior here than at Sharks.
FKK Sharks is a HUGE FKK Sauna Club brothel on the North side of Darmstadt. They excel in the warmer months because they have a large outdoor area with a grill, pool, and lots of lounge and picnic seating, plus small huts for adult fun. Inside is a multi-level playground with a large central bar and lot of seats. Like most of Germany, heavy on the Romanians, but usually quite a few 8+ ladies DTF for €50/hh, though some have suggested the girls are pushing more for either hour mins 100/it. Frankly, at my mid-40s age, I either need one quickie and a full hour with number 2, or two full hours with the right girl. FAIR WARNING: this place relies on AC, being a converted warehouse, so in a heat wave, I've heard it gets toasty here.
FKK Mainhattan was a one-time trip, and my first FKK experience. Don't recall the girl, but the place was surreal in 2011. Near a tram stop (Straßenbahn) of Daimlerstraße in FFM.
FKK Sunshine in Munich, kind of a tiny place with not much of a restaurant and nowhere to go that doesn't have ladies right there when you want to take a break.
Now, if we had a Swiss Subpage, I could tell you more about Club Globe. Yes, I know, everything is more expensive in Switzerland.
Agencies I can recommend
Most reputable agencies focus on multi-hour and higher dollar clients. Most of the higher end escorts in Germany are German ladies in their 20s-30s doing this on the side.
One way to know if you're dealing with a reputable agency in Germany is to see if they're open about ownership. Kay and Tia are open about proprietorship, and all of these have "Imprint/Impressum" pages identifying the ownership.
I've met ladies from all four, multiple with Tia, who was my first German agency back in 2011, and have seen one of Kay's ladies (Aliyah, a short blonde who I believe is currently only shown on their VIP page - I can't currently confirm) several times the last three years. She is a €750/1.5 hrs lady in FFM. Virtually every agency lady I've been with was fun BCD. The most memorable one barely spoke English and was all over me once we got back from dinner. That was in 2011 unfortunately and she's long gone. Tia maintains an updated schedule, which is helpful. Also note that you may find some of these ladies on other legit agency rosters. One of Tia's ladies in Munich is also cross-posted on Target, for example.