Don't think you need to advertise here ...
I was in Amsterdam a couple of months ago, put myself in a sling at NZ Sauna and there was no shortage of willing fists. An amazingly wonderful experience ... https://www.saunanieuwezijds.nl/
And then there is club church https://www.clubchurch.nl/index.html My eyes were rolling back in my head by the time I left there ...
And here's the complete guide to Amsterdam fisting .. http://www.fistrik.com/