what is your writing environment like? how do you get yourself in the mood? I'm trying to write something that is both cathartic and dissociating to relive and its hard to feel like its every the right place or time
Hmm, in the case where you're trying to capture a particular ambience or mood, I'd say it's really important to not focus on getting it 'right' the first time, because then it's less about right place/time. Don't forget the really important role editing has in writing, where you can punch out the emotions, or dial them down, or change the weighting, etc.
If it's something you need to get out of your system to write, starting with bare bones or sentences is an okay place to start. I'm always fully aware that with my most emotional scenes, they will get their true strength in the edits, because the first part is just getting it all onto the page.
In that sense, I'm quite pragmatic. My writing environment suits my body - I sit the right height for my keyboard and screen, my wrists rest comfortably on the desk, I'm in an ergonomic chair, I use a mechanical switch keyboard etc. It's not about the vibe exactly, it's really about making sure I can do this job in a long-term way without fucking my body up permanently. I work on a desktop, and I usually have meds / water / notebooks / research / stationery within easy reach. Sometimes chocolate, too.
I don't really 'get myself in the mood' to write, I think this is something hobby writers can sort of afford to do, that professional writers can rarely do anymore, because it's more of an indulgence. For example, with art, I only do it when I'm in the mood to do it. Because none of my bills are dependent on that. It truly is just vibes based.
But with writing, I have to show up and write even on days I really don't feel like it, where I can't find the zone etc. That doesn't mean it's not worth doing things that help, it's just that, I can't wait for the 'right feeling' to come along. I have to actually just do it. I have 8-10 writing deadlines to meet each month re: putting up chapters, which means to make sure I'm not falling behind, I have to write at least 8-10 chapters per month, and edit them all multiple times. There is no 'mood' to guarantee that always feels great / right / good. (This is also where editing can help, because if I write on a day where my writing isn't as good as another day, editing can fix that - that's literally the job of editing).
Outside of that, it's worth using or looking into noise generators like mynoise.net - to specifically find the right sort of sound atmosphere if a playlist won't work. Stephane makes everything from forests and beaches etc. in different countries, to ambient cafe noises and office noises so you can imagine you're in a white collar job or at a local cafe etc. Otherwise I'll use a Spotify playlist, and make a lot for different characters and stories.
I also like using Focus Writer, a word processor where I can use different backgrounds to set the mood - such as a gloomy stormy forest scene for Gary, or a screenshot from the House of Hope in Baldur's Gate 3 for Palmarosa.
I would also say... be careful writing something that's going to retraumatise you. That's not a great idea. If it's causing literal dissociation, it's not necessarily going to be super cathartic to write, it might actually be retraumatising instead (catharsis transforms emotions in a healing way, retraumatising can just be feeling them intensely enough to dissociate while getting none of the catharsis, only you can know the difference - but it's good not to write in a way that hurts you).
It can be good to check in with yourself re: whether you're ready to write that scene, and/or if you're focusing too much on your own experiences and not the character's experiences (unless you're literally writing self-insert, the character should not be a carbon copy of you, and will have their own perception and feelings about events - sometimes refocusing into the character helps me to actually not hurt myself while writing scenes or moments very similar to trauma I've actually lived through). Like, in cases like this, it might literally be that your body is telling you that you're not ready and it's not safe yet to write this, and that's why you can't get into the mood to write the scene. Not everything is about writing set up! Some of it gets pretty deep.