Here's a reference for anyone having trouble getting a scene, or wondering if they've got them all. Rather than outline full play paths, I'll just describe each scene and how to get it. Spoilers ahead, of course.
With the ear clips equipped, lose three times to any of the normal enemy groups to get all three scenes. Note that losing 3 times will lock you into the Slut Mode path, so you won't be able to get the normal endings without a separate save.
-Slut mode battle sprite
After losing three times to normal enemies, battle sprites will be different, and clothing will be optional
-Normal mode good end
Defeat Diezel in normal mode. No CG, but listed here as it is an end.
-Normal mode loss to Diezel
Lose to Diezel in normal mode. Choosing not to surrender fully at the end will start a loop. Choosing to fully surrender will complete the scene and lead into-
-Normal mode Bad End
As described above
-Slut mode end
Fight and "Defeat" Diezel in slut mode.
-Lose to stair guard
Lose fight to stair guard in normal mode
-Give in to stair guard
Give into stair guard's demands in normal mode (immediately or after a loss)
-Get used by stair guard
Talk to stair guard in slut mode