you don't have to sleep with her the first time you talk to her, just get her excited to see you every time she goes to the laundromat
after 3 or 4 times just hanging out while you wait for your clothes,
this made me laugh a lot for some reason.
probably because in my head i'm picturing her going "ooh! dirty panties, now i can go meet THAT GUY~!"
and then after meeting, they're clean.
the ninja answer is find some way to sneak off some of her clothes and pull a 'whoa how did this get here this isn't mine excuse me is this yours' after she's started washing them, offering to throw it in with your clothes since you two seem to share similar laundry times.
but if you aren't skilled enough to do that, you literally have a bag of clothes. SOMETHING in there has to be attention grabbing, besides the underwear.
--
The future must protect the clone's past.
"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.