Hi! This is my first time ever making a post, but I have been using this community forever to find great fics!
Unfortunately, I can't find one of these fics, but I remember part of it. Sam and Dean have been flirting slightly, and one night Sam thinks they are going to do something about it. They stop at the Roadhouse, where they encounter Jo and a trained and professional hunter Cassie, both who are flirting with Dean, and Dean seems to be interested in both of them. Sam, feeling that he has misunderstood Dean's intentions, goes back to the motel dejected. I am not quite sure what happens from there, but I'm pretty sure it was a happy ending.
Thanks for helping!