I found myself in Prague with an evening to kill. I ended up spending 12 hours at Sauna Club. Cost to enter was 2000czk, about 104us$. In & out privileges included, alcohol extra.  It is a fairly new club and very well laid out - two saunas, hot tub (unfortunately not hot), bar, buffet, lots of play areas, private curtained cubbies, upstairs rooms, and lots of very nice showers.  There was a wide range of girls, local & Bulgarian, Romanian, etc. They are not at all aggressive and will leave you alone if you are not interested.  I managed private time with 3 girls, four separate hour long sessions with one, Alina, a 23 yo Italian-Romanian who I really liked. I spent $800 total, which was more than necessary.  I liked Sauna Club more than my only other FKK experiences, which have all been at Dolce Vita in DUS. This club alone is worth a side trip to Prague.

http://www.saunaclub.cz/