She is uncomfortable with her sister wanting to strip her in front of the admiral, and kasumi not wanting to stop them is as guilty as anyone XD. The admiral will obviously enjoy the show.
What's more surprising is that Kasumi doesn't really object him ogling incoming pantsu-shot
Oh~What!?Commander!!Isn't modifying the standard uniform against naval protocol!?Nee-san, aren't you exaggerating things?Arashio!! Take that off right now!!I'm already prepared for it.You piece of trash...Nee-san, you should have some sense of humour!!Hey...AraInexcusable.AsaI won't be responsible for whatever comes next, alright?