Looking for lesbian roommates story, lesbian awakening type, please help!!

[iaalaiapoi]

This story is about two college flatmates, in separate bedrooms but shared bathroom. The MC is very conservative, virgin, no sexual experience. She finds the vibrator of her flatmate in the bathroom by accident. It fascinates her and she buys a similar one online, but she tries it and doesn't like it because she doesn't know how to use it. They end up talking about it and the flatmate then shows her how to use it, effectively masturbating her. They had been lusting after each other for a while but the protagonist thinks she is straight, and learns later that her flatmate is bisexual. The flatmate has never been with a girl before, only with a guy. The MC and the flatmate ends up together.

I read this story a few years ago and it's driving me crazy that I cannot find it anywhere. I'm pretty sure it was on this site, please someone help me find it!!!!