I like to use GoogleDocs as far as like, full-on planning is concerned. But for chatting about the planning, I use discord and twitter and google-chat, too.

I did want to clarify though, when I originally read the post I focused more on the consent part than the kink part. I don't know how you wanted to focus the panel, if it's chosen, because I don't know if I'd be much help in the kink department. All of my consent examples that spring to mind are more vanilla, they just occur in a high stress/anxiety type scenario.