It's pretty straightforward actually: just enable the maledom content and pursue Octavia romantically, the scene will happen during the last sex event that is currently present in the game.It must be pretty well hidden. Even with multiple playthroughs, cheats and a gallery unlocker I've been unable to find any WS content whatsoever.
If you still have troubles, I can share my save game (give me your preferred name for the mc, in case)