Dunno if you have finded it yet buuuuut, you can unlock the bdsm part with the making out minigame.
Yeah there was a bug that the dev fixed in one of the recent builds.
I had done dang near a dozen of each (makeout, vanilla, and spicy) to try so many options when I had asked so I knew I should have unlocked the 'give Hex the pretty things' switch.
