Cheat mode is still kind of weird, I've been unable to trigger any training scenes at max dexterity even in the current version, so I used the console command to remove dexterity (like the console commands in the OP, but replace the word 'append' with 'remove') because the game still expects you to have zero dexterity at this point.
This unblocked the sister story for me, I was able to train twice with master somrak then wait for him to ask for more panties. Only then could I get past the sister diary scene.
