The sound of metal scraping against walls was what alerted Castiel to the fact that he was not alone in the bunker as he had thought. Cocking his head, he stood from where he was seated at a table, reading about something that humans called "marshmallows". They were a strange confection, in Castiel's opinion. All the same, he would like to try one. Maybe he could convince Dean to get some after the next hunt. Castiel walked around the large table in the center of the room, towards the source of the noise. Suddenly, Dean's slightly muffled voice reached his ears.
"Damn it, Cas! Could you give me a hand here?"
Turning the corner, Castiel saw Dean trying to move a large metal contraption through the hall that led to the front door. Somehow, though, Dean had gotten himself wedged between the metal object and the wall and appeared to be stuck. His face was red and he struggled futilely against the cool metal that had pinned him.
"Dean. I think the metal contraption has won this battle." Dean glared at him.
"I'm not fighting it! I'm trying to get it outside."
Still slightly confused, Castiel walked a few paces forward and put two fingers to Dean's brow. He tried to ignore the thrill that went through him every time he touched the human. In the next moment, they were standing outside, Dean free of his metal opponent and Castiel inspecting it.
"Dean, what is this thing?" It didn't look like anything he had encountered in his lifespan.
"That," Dean huffed, "is a bike. A very old, very difficult bike."
Castiel looked up at Dean in confusion, which wasn't that strange. It was his usual expression when he was talking to Dean.
"Why do you need a bike? You have Baby." He had heard Dean's nickname for his beloved car and had called it Baby ever since. He liked the small smile that caught the corners of Dean's mouth up when he heard Castiel's reference to his car.
"You told me you didn't know how to ride. So I went to the garage and looked to see if any of the Men of Letters had left a bike here."
Castiel backed away, suddenly apprehensive. "That's really not necessary, Dean. I have my wings. I do not require this metal bicycle to transport me anywhere."
"I know that, Cas," Dean rolled his eyes. "But everyone should know how to ride a bike. It's part of life."
"But-" Castiel was really starting to panic, but Dean cut him off.
"Come on, Cas."
And when Dean asked like that, when he looked at Castiel like he was the only person in the world, of course Castiel was going to say yes. He had never been able to resist Dean's pouty face.
So they spent the next twenty minutes cleaning off the bike while Dean explained the basic concept of riding. Castiel tried to stay calm, but the longer he listened to Dean's words, the more nervous he was becoming. Finally, the bike was ready, and so was Castiel, according to Dean.
"Alright, Cas, up you go." Dean smiled at him in encouragement, but Castiel resisted the urge to obey. He looked doubtfully at the bike. Dean sighed in exasperation. "Cas, get your ass on the bike. Now."
So Castiel climbed on the bike, not liking the hard and uncomfortable seat or the way the bike wobbled to the side every time he tried to pick one of his feet up. How was he supposed to ride the contraption of it wouldn't stay up? But Dean, ever patient, helped hold him up as Castiel put his feet on the pedals and started to move. The first couple of tries, Castiel only made it five feet or so before he felt the bike wobble, making him quickly put his feet back on solid ground. But in the next few hours, Castiel was able to go farther and farther, Dean looking on proudly. Dean's happiness was what made Castiel keep tying, otherwise he would have smote the bike after his first fall.
"So, what do you think?" Dean asked after Castiel had circled back to him. Castiel smiled.
"It's fun. It's almost like…flying." Much slower, granted but the feeling was the same.
"Told you so, didn't I?" Dean smiled, proud of both of them, and Castiel felt a warm glow in his chest. "Alright, one more go and then we'll go get some grub."
Castiel nodded and pedaled away, looping towards the drop off beyond the road so that when he turned around, he would be right at the door of the bunker. Everything was going well until the front wheel of the bike caught and got stuck on the root of a tree. The bike tipped forward and suddenly Castiel was staring down the side of the mountain. His momentum kept him moving forward while the bike stayed behind. He tumbled over the handle bars, a strangled yell coming from his throat. Distantly, he heard Dean yelling behind him.
"CAS!"
In the next second, Castiel spread his wings and flew to Dean's side. However, his trip over the ledge had thrown off his aim, so instead of landing standing up beside Dean, he appeared in a headfirst dive several feet above Dean. He crashed down on top of Dean and they both went down, tangled in each other's arms and legs and getting covered in dirt. When they rolled to a stop, Castiel was on top, face to face with Dean. His human was looking up at him, stunned. His wide green eyes were flicking over Castiel's face, checking him for injuries.
"Cas, are you okay? You-" He stopped when he saw the dangerous glint appear in Castiel's eyes. He was wary as Castiel lowered his face even closer to Dean's until they were only a centimeter apart.
"No more bikes," Castiel hissed. And with one glance, he made the bike melt. Dean stared at him for a moment, and then started laughing. Castiel glared at him.
"Alright, Cas," he chuckled. "No more bikes."
Castiel nodded and extracted his limbs from where they were bent around Dean's. he stood carefully and brushed the dust and dirt off of his trenchcoat. Dean did the same and then walked over to sling an arm around Castiel's shoulders. Dean was smiling at him and Castiel felt his anger at the bicycle melting away the longer he stared into the hunter's eyes.
"Let's go get some food, Cas."
They walked back to the bunker, leaving the twisted and still melting remains of the bicycle behind.