I see him in the Antechamber, but I am clueless as to how to dance with him. Help, please?

I just figured this out~

I needed 2 tabs open

Keep the antechamber open in one, use the other to go back in time via the coda caves. Then hop back over to the tab with the antechamber and click the fox-man. You should get a page with a little dialogue and a link to ask him to dance.

Make sure that you are in the past and then click this link: Fox Man.

[edit]Ryn beat me to it but my way is a "shortcut" of sorts:)