Well that kind of depends whether you’re sleeping in the same bed for convenience or because you’re getting intimate, but I’ll assume the former.
So, you have the boring option of doing it in the bathroom and elsewhere.
Depending on what she’s like, and how you think she’d react, a more fun option is to go for it, try to do it secretly in the bed, just moving your finger, she… probably… won’t feel it. Until you get close that is. Then you’ll start going faster and harder… what will she do, will she just ignore you? Will she say something?
You can cum if she accuses you of masturbating, but you have to cum just as she says it. That’d be fun.
Or even more fun…you turn to her in bed, and say, ‘so do you know what edging is?’ and then read my blog together. Make sure to linger on the ‘denial buddy’ bits
https://female-orgasm-denial.tumblr.com/tagged/denial-buddies/chrono
‘It starts with a dare…’