Edit Note: minor edit made to remove a reference that didn't really fit with the tone of the piece (see reviews).
General note: This is just a little piece playing with how far I could push the Yang in denial idea so a bit exaggerated over my AU cannon. This story is marked complete because I'm not intending to write more around this specific scene (so no more chapters on this), but it is set in my After that Day continuity. I am working on several other stories in that AU at various stages of completion - including a few more on the Ruby/Weiss relationship "thread". tl;dr - if want more of "this" follow my author account not this story.

Yang was pretty good at the domestic stuff, and the team was all too ready to take advantage. If she was happy to handle all the laundry, why not let her? No problem, mostly.

"Does Weiss think I am a pervert?"

Ruby glanced uneasily at her big sister, trying to gauge context. Uncultured barbarian wasn't the same as pervert.
"No. She just ... um." Ruby decided to stay positive, "She doesn't think you are a pervert."

Yang suddenly seemed to realise the question was a bit strange
"She said I did a good job in the past. She would say if she just wanted them done separately, wouldn't she? And you know since it is just the panties..."

Realisation dawned for Ruby
"You haven't been seeing Weiss's panties in the laundry?"

Yang nodded.

The younger girl hesitated. Yang was open enough about her own relationship with Blake, and even used to tease her sister about Weiss... but that was before. Her big sister had accepted 'dating' but she aggressively maintained ignorance on the matter of Ruby's innocence or lack thereof. Yet she apparently acknowledged her as an authority on Weiss-panty related matters. It was a delicate situation. She wanted to give Yang space to, as Weiss emphasised, peacefully accept things in her own time, but equally she didn't want to start lying to humour her.
".. where she would put them after wearing them..." Ruby paused again hoping lateral thinking would kick in.

Yang just looked at her expectantly

Under Ruby's influence Weiss had embraced her inner naughtiness with a number of little games. Intuition suggested Yang wasn't looking for a discussion of Weiss's new love of ventilation, and certainly not the effect it seemed to have on normally cool girl's libido.
"The thing is that lately she doesn't often wear, um. Since we've been err, she likes to..."

"Ah!" Yang's sharp exclamation made Ruby jump, "I see how it is." She gave Ruby a grin and an exaggerated wink.

"You do?" That seemed way too easy.

"You like to match now!"

"What?" Match? There was no point in going bare with tights, and her thigh-highs affected Weiss in a way that, although gratifying, was safest kept in private.

Yang slapped herself on the forehead
"And that's why it seemed like yours kept ending up with her stuff"

"Err..." Ruby goggled at her usually worldly sister.
Ruby searched her memory for recent cases of underwear displacement. She supposed by stuff Yang meant clothes; well, probably clothes. Weiss could be hyper-focused when she got excited and tended to forget other things. The less said about spending half an hour frantically searching the Headmaster's office the better... Many pairs were MIA, but she was fairly sure that as well as pockets 'stuff' could legitimately include Weiss's book bag after 'studying' in the library, text books after taking the scenic route back from class, handbag after shopping in Vale, a picnic basket, gym bag... ok maybe the last one was almost innocent, if you didn't know how it happened.

"Matching," Yang chuckled to herself, "you guys are so precious." Yang hefted the laundry basket and bounded out of the room.

Ruby sighed. This cheerful denial thing was getting stressful. It almost seemed like her father handled it better, uncomfortably awkward for a while, but back to normal quickly enough.

"This is not going to end well" Blake's words seemed to echo Ruby's thoughts. The Faunus held out a pair of Ruby's underwear, suspended delicately between finger and thumb.

"Thanks, um, where-"

"Behind the bookshelf"

"Oh yeah, I remember. Weiss... stuff you don't want to know" Blake nodded gratefully. Ruby backed out of the room, "I'll go give these to Yang"