Navigating fan fiction archives feels like wading into a sea of possibilities, and for this specific pairing, you're looking at a niche within a niche. The most consistent source I've found for that kind of content is dedicated fanfiction websites, particularly Archive of Our Own (AO3). Their tagging system is incredibly detailed; you can filter for the 'Ino/Sakura' pairing, then add tags like 'Explicit' or 'Lemon' to narrow things down. Given the explicit nature, you'll need to have an account and set your preferences to view mature content. The quality varies wildly, from short, playful scenarios to longer, more developed narratives that explore the tension and rivalry-turned-into-something-else dynamic between them.
Another spot to check, though it requires more sifting, is FanFiction.net. Their moderation is stricter, so explicitly adult stories often get purged, but some authors use coded language in summaries or move the most explicit scenes to external links. It's a bit of a treasure hunt there compared to AO3's more open policy. For a more curated, community-driven feel, sometimes small, independent forums or blogs dedicated to Naruto femslash or specific kink themes will host these stories, but they can be harder to find and aren't always as reliable for consistent updates. The dynamic itself—two kunoichi with a complicated history, moving from competition to intimacy—offers a lot of material for writers who enjoy exploring power dynamics and emotional complexity within a familiar setting, so the stories often focus on that push-and-pull as much as the physical scenes. I always make sure my ad-blocker is active on any site I use for reading, as some of the smaller ones can have particularly aggressive pop-ups.