Friends w/ Benefits?!?!

Okayyy so how many of y'all were in a friends with benefits situation and how did it play out? Looking for your good and bad stories!

...I also may or may not have started one, and I am a little nervous about it, I guess. I am extremely close with this guy and a few days ago we kinda messed around, and then, we just kinda... continued? I really like him romantically as a friend, but I guess I want to hear what kind of outcomes happen when you cross into new territory like this.

Any stories or advice is welcome!