Nevermind I have done it now. I kept making her swap clothes until she got annoyed but then stopped. Kept trying to swap her clothes after that and a new scene happened.
I've done Cassie's story up to the point of kidnapping Alissa and having her interupt in the bed and the bath and I've kept swapping Cassie's clothes to annoy her. What's after that? The log book tells me to hang out with them both I'm pretty sure I've done everything.