There is all sorts of possibilities in Germany, some estimates put the number of prostitutes in Germany at half a million. It does depend a bit on where you are though. Some bundeslander (Saarland and Bavaria) don't allow BBBJ, some don't offer that many options and some have more brothels then you can count.
Read local sources or websites like
sexdo.de
6profis.de
and similar... I don't really use websites
FKK clubs work like this:
1 pay entree fee
2 stay as long as you like
3 drink is free
food is free
wellness is free
use of the rooms is free
really, after you pay the entree fee your business with the club is done (unless you like liquor)
4 see if you find a girl you like
5 talk to her and if necessary discuss what you like (not prices, those are fixed)
6 Go to a room and do whatever you want. P
7 pay the girl
8 Repeat ad nauseum til you're done, out of money or the clubs closes
You're budget should be fine for a daytrip with about 2 or 3 hours in a room; either with 1 girl or 4/5 different girls