This one is going to get a little smutty. I tried, but it didn't really turn out how I thought.
"Sammy, knock it off!"
"No."
Sam was leaning over in the car with his arms around Dean, kissing and biting at his brother's neck. Usually, Dean enjoyed his type of attention from his brother, but he was trying to drive. Sam continued. Dean felt him slowly slip his hand underneath his shirt. He clenched his jaw and stared straight ahead, holding back a small moan.
Without thinking too much, he swerved off the road and parked the car. Sam unlatched himself.
"What are you doing?" he asked.
Dean opened the door, got out, and walked over to the passenger side.
"Get out" he said sternly, opening the door for Sam.
Sam gave a confused face, but reluctantly got out. Dean suddenly shoved him against the closed door and smashed their lips together. Sam quickly kissed back. Dean began to unbutton Sam's shirt and kiss down his body, ending right above the waistband of Sam's jeans. He stopped for a minute to look up at Sam. Sam was gripping onto the car and chewing on his bottom lip. Dean stood up.
"Calm down." he said, giving Sam a small hug.
"What if someone hears?"
"It's late, there is absolutely no cars out, just don't be too loud." Dean chuckled.
Sam nodded, and Dean went back down onto his knees. He unbuttoned Sam's jeans and let them drop to his ankles.
"Remember: keep it down, okay?" Sam nodded again.
He swiftly yanked Sam's boxers down. Sam gasped as Dean sloppily kissed his inner thigh. Suddenly, Dean begins to deep throat his brother, trying not to gag. He bops his head up and down.
"D-Dean" Sam half stutters, half moans.
"hmm?" Dean hums, making Sam moan louder. He tangles his fingers in Dean's short hair and pushes his head closer, making him move faster.
"Dean, I'm going to --" Suddenly, Dean feels him cum into his mouth. He swallows.
Dean stands up, quickly wipes his mouth, and pulls up Sam's boxers and jeans. Sam is breathing heavily.
"What was that for?" he asks once he catches his breath.
"That was payback for teasing me in the car" Dean says casually. Sam laughs and pulls him in for a kiss.
