I'm looking for a good swinger club (which will admit single guys), preferably one with an FKK day (or at least one where at least I can be nude; I am not into dresscodes), in or near Aachen. Any recommendations? A traditional partytreff, if any still exist, would be interesting as well. (Doesn't have to be flatrate, as long as it is 12 coins for EUR 100 or whatever for several hours.).