I just remembered what it was. There's a trophy for PS4 that requires you to get all of the gestures but one of them is locked behind interacting with Roasaria's Fingers, but if you do that it cancells Sirris' quest line. You have to do it before Abyss Watchers fight but Sirris' quest goes way past that, or at least the part where she gives you a ring you also need for a trophy.
Yes of course, this applies ONLY to get endings, and not items or spells from different quests.
Also you can still interact with Rosaria's Fingers AND get the covenant achievement, the important thing is, you just need to JOIN the covenant without offering her a pale tongue.
If you do so, Sirris will turn hostile locking her quest out.
If you only join you are safe and you can do Sirris' quest normally (I did exaclty this, since I thought I screwed up myself, but if you don't level up the covenant, you are safe).
In my example, I didn't know about gestures, so I missed some because I needed to summon some NPCs before killing the Lords, but I didn't follow a guide so probably I missed a lot of things in and there.