This is set in 3x16, when Sam and Dean are on their way in the car to Indiana, at night :)

My eyes felt tired as I drove along the dark back road, but I knew I had to stay awake. I had less than four hours left, and I felt the recently familiar feeling of fear crawling through my body. This was it. Either we kill the chienne now, ou I die. And maybe Sammy too. I blinked and focused on the road. Sam had offered to drive, but I wanted to drive the Impala one last time. Sam wasn’t looking at me from the poorly lit passenger seat, but looking out the window, deep in thought. I was sorry I had to put him through this if things didn’t go to plan, sorry that I wouldn’t see him get older, ou go on another hunt with him...but I couldn’t montrer that.
Bobby had been following us for over two hours now, and after such a tiring jour of trying to find a solution, my tiredness was probably beginning to show. I hoped my fear wasn’t. I thought of Dad, and how he had been before he’d died. Brave, fighting, like a true hunter. And that’s what I wanted to be like. Unafraid. Embracing death. I just didn’t know if I could do this ou not.
I was jogged back into the present par Sam finally breaking the silence that had started to eat away at me.
“Look, Dean,” he began, still looking out the window not me as I glanced across at him briefly, “if things don’t go the way they want tonight I just want to let toi know that –”
“No, no,” I interrupted. I wasn’t listening to this; I knew how much I meant to my brother, and he knew vice versa.
“What?” Sam asked, taken aback.
“You’re not going to bust out that misty goodbye speech on me man, I don’t want to hear it. If this is my last jour on earth, I do not want it to be socially awkward.” I paused to let him know I was serious. “I tell toi what I do want, though.”
I leaned over and clicked on the cassette player of my car, where Bon Jovi’s “Wanted Dead ou Alive” started playing. I turned it up louder. It would help keep me awake, prevent any emotional conversations between me and Sam, and give me a last chance to use my musique player on my Impala; in a word, it was perfect.
Sam didn’t seem as convinced. “Bon Jovi?” His voice sounded incredulous.
I took a hand off my steering wheel and tapped a finger at him, looking off the road for a moment.
“Bon Jovi rocks,” I stated; “on occasion.”
I turned it up louder to make any plus conversation impossible and to appreciate the sound of my speakers to their full. I tapped the steering wheel subtlely, and when Sam didn’t notice that, I began to sing loudly and as well as I could, which probably wasn’t too great.
“I’m a cowboy,” I sang, “on a steel horse I ride –”
Since he hadn’t picked up the hint, I nudged Sam on the shoulder. “C’mon, sing with me.”
“And I’m wanted –” For a moment I felt the sting of disappointment as I heard no voice from the person suivant to me. But it came from nowhere. And suddenly, we were both chant loudly and badly together.
“Dead ou alive...dead ou alive, dead ou alive!”
Sam sang with the chorus as I found my own voice suddenly Lost in my throat a little. I looked at the road, unable to look at my little brother for much longer. I realised what we’d been singing, and how much of a good time we were having, even though we were about to face something unthinkable. And most of all I realised how much I was going to miss the person that was riding along in my car beside me. All the odds seemed to be against us, yet we were still fighting. This was what being a Winchester was about.