There's half a dozen Chinese massage shops in and around the centre and the odd Thai shop, if you do a Google search you'll find them - cant recommend any as I never got around to trying any despite many visits to the city. You're only 25 mins from Amsterdam as an alternative. The various local authorities in some of the Dutch big cities have been clamping down for the last few years on anywhere offering sexual services that isn't licensed to trade as a brothel and that's closed a lot of "legit" type massage shops temporarily or permanently. If you do go and see a sign in the cubicle written in Dutch it likely says please keep your underwear on - best bet is to play the dumb tourist and ignore it and hope for the best. I don't doubt you'll get FBSM massage from one of them, you just might find more misses than hits if you're not a regular.
