Part of "Dancing With Dust" canon, but not necessary to read beforehand.
Vinyl is mute due to an accident.

Octavia and Vinyl are going to hang out today...except that Vinyl is late. Again.

Octavia goes to get her...and finds she's still in bed.

She then learns a couple of things about her best friend. One being...she sleeps nude. Second...they actually do have something going on between them.