Sex / kink stuff is a grey area in most states, save for maybe Nevada. The city just never recovered from the destruction of the Combat Zone. The "adult entertainment district" runs for one block on Washington Street from Stuart Street to Boylston Street / Essex Street. It's so heavily gentrified it'd be impossible for a sex club to turn a profit and pay rent in that area. Luxury apartment complexes now occupy a good 75 percent of the zoning district.

Boston's kink scene got forced underground after a police raid in the early 2000s and stayed that way ever since. In my opinion, a lot of the legal issues aren't particularly relevant in 2022, but finding a venue for a "technically illegal but unlikely to result in legal action" activity is difficult. And I think people like the underground nature of it and resist attempts to make it more mainstream and accessible.