Another "Hop across the border" vote. I'd head for Acanthus near Kortrijk on a Friday or Monday night. Swinger club rather than punting den but plenty of full on action.
€110 Friday €90 Monday gets you in, unlimited food and drink ( within reason ).
On the N50 between Kortrijk and the venue on your way you'll pass about a dozen "Clubs" if you really want to go for the punting option.