So after finally realizing this was an option, I went to try and see this scene and found that none of my Champions could access it due to all my runs picking the 'No Way' option when seeing the initial conversation as part of the Cat Call quest. Going back to earlier saves with several of them, I find they can unlock the threesome option if and only if I accept Evergreen's initial offer and let Cait join in. Refusing or not letting Cait participate locks the content out. I asked in the Q&A board if this was by design or not and Savin said he thought it was intended to be open, so I'm making a report here if it is indeed a bug and not meant to be gated content.
I can share save files if it's necessary.
I can share save files if it's necessary.
