Two sticks in a fire is a gay sexual term best described as the penis rubbing against another male's penis until further long ejaculation.
Guy 1: I had a good timelast night Guy 2: Oh really? What happened?
Guy 1: we rubbed our penises together
Guy 2: Did you ejaculate right?
Guy 1: it was the best sensation of my entire life
Guy 2: More like Two Sticks in a fire that night you had together
Another reference to when two dudes try to stuff both of their man meat into a chick's pussy. I'm not sure where the origin came from, but I heard the term used on Eminem's response to Mariah Carey's "Obsessed".
"...When me and Luis were tryin to stick two CD's in the same slot."