Plain and simple, say what you need to - get it out with your T, as needed. The comment on vulgarity was meant to say I have always approached that stuff with some delicacy and euphemism unless my T thought more information was needed. My T is a person too and I let her direct me on how much detail she needs.I shouldn't say things in detail? Like if I were going to say things I don't know what I should say like my t has said you can say he's touching me here or making me do x or y and that is vulgar but it is part of what happened.
EMDR does not involve reviewing the details over and over the way exposure therapy does however. In EMDR the first part is to look for where the narrative starts to break down. Where it turns to "shattered memory" is where the trauma likely is. Then you can hold how that memory made you feel in your mind and the reprocessing EMDR does changes how you feel about it and allows it to process. I have never told my T more than what she asked for. Yes we drilled down for details here and there but mainly to get to how I felt about the memory. I walked in thinking I knew where the trauma was and where it came from. The true answer came later, after months of EMDR and it surprised even me.
I found that I never needed to detail much outside the exact moments that caused my trauma. Plus I couldn't detail or tell a narrative because as things came back to me there was the "shattered" memory effect Bessel van der Kolk describes in "The Body Keeps Score" where there are bits and pieces I can give some logical order to. But in the end - I couldn't give you a narrative a,b,c,d story like I could to the memories where I thought trauma was.