Hmmm - this pricing structure is new to me. Anyone else?
I have been to a few FKKs (Wildenrath, Palace and Oase), and I can absolutely recommend trying it out. In all three places I went, you pay the cover charge once (65 Euro or so), and generally 50 Euro for each session. You can stay the whole day/night, relaxing on the couches , hot tub, or outside in the summer. The women basically wear high heels and a smile. That's it.
This 130 Euro, sex with each woman (but only once) seems like a great deal, but I wonder what the catch is - are there only 5-6 there? Howe many other dudes are there? Do they have time to brush their teeth after BBBJCIM?
In the Frankfurt area, I suggest
http://www.fkk-oase.de/en/home.htm(requires a map, rental car and patience), or in town try
http://www.the-palace.de/galerie_en.php
Not the cheapest way to hobby, but the experience is definitely memorable!!