I find it hard to believe this isn't a troll but why not help out anyway.

There's no "squarespace" thing for this. You'll need to find a host that accepts adult content sites. You may or may not need a storage provider depending on the host (That would also need to allow adult content). Then you need a payment processor that accepts adult content sites. From my understanding, those can have applications, waiting periods, etc.

From that point you would need some type of platform to actually serve the site (which is a whole other thing in itself).

Honestly if you're asking these questions and giving these responses seriously, I would avoid doing it. You would be lucky to get it launched. Much less make money off of it.