Yeah, navigating fanfiction communities, you start picking up where certain pairings, especially the more mature ones like Hinata x Sasuke lemon stuff, tend to congregate. A lot of that content naturally flows onto Archive of Our Own. The tagging system there is pretty robust, so you can filter for explicit works and that specific pairing. The writing quality varies wildly, of course, but the volume is there.
I've also seen quite a bit pop up on dedicated Naruto fanfiction forums from back in the day, though activity there has definitely slowed compared to the big archives. Sometimes the older forum-based stories have a different, almost nostalgic feel to them, even if finding them requires a bit more digging through old threads.