It would be funny if you had to use the Konami Code in order to activate it during Free Mode.
But I will assume that it will be related to H-exp and a new skill, right?
Also, as a test, you could try to see how compatible is with non-tall females by reusing the Birthday Event Animations with the nest females with similar animations, like:
-Bunny: TC's anal
-Harpy: Blondie's thighsjob/Vaginal
-Slime: since she has a rigging for oral sex