Kill La Kill: Mind the Changes (Patreon)

 Satsuki sits peacefully in her study until Ryuko asks if anything seems off to her sister. They try to think over what could be wrong, but it's rather hard to do when you're so casually getting your ass eaten out by the president of the mind control club. 

The story is available on Patreon now, and will go on HF and AO3 in two weeks.