Castiel did not like to be surprised. He saw being caught off guard as a form of weakness, and the word 'weak' and 'vampire' should definitely not be in the same sentence. He hated surprises as much as he hated werewolves, and his new human acquaintance was really starting to tick him off.
He stared at the bag in his hands, mouth slightly agape, and contemplated what he should do. It was filled with a bunch of smaller bags of blood and he could just feel the drool pool up in his mouth. He knew Dean was looking at him with expectant eyes, waiting for him to say something. A 'thank-you', perhaps.
"Dean I, um, appreciate this, I do, but-" he had to advert his eyes at this point to avoid Dean's almost brokenhearted and confused gaze. "I, I can't accept this," he whispered.
Bullcrap, Dean thought. The guy chooses now to be modest? "And why can't you?" After all the trouble Dean went through to get the stupid bags of blood, the least he could do was accept it and release the obligation Dean felt on his shoulders.
Cas took a deep breath before answering, although this did nothing but make the smell of fresh blood flow through his nostrils.
"I can't accept this because-" he hesitated. He tried to think of a better excuse as to why he couldn't accept the kind offering. He figured that saying that accepting free blood from a mortal whilst his brethren had to vigorously hunt for their share was unfair and wrong, but that seemed like a weak argument. They would smell the blood on him, that was for sure, but it's not like he could share the blood with them either. He knew that they would demand to know where it came from. Lying wasn't an option, since vampires could always tell when you tried to pull a fast one on them.
"On second thought," Cas began. He decided that he could use a vacation away from the pack for a little bit. "I guess I could take these off of your hands..." He knew that accepting the blood meant that he would have to distance himself from the nest for a while, and he knew he would gladly do it. He couldn't let them find out about Dean, he just couldn't. Dean was his human. He felt a weird sort of obligation towards the strange mortal, and so he would protect him from his fellow vampires.
Dean let out a sigh of relief. Now he wouldn't have to try and return the blood and face Sam's ridicule. He could just feel the obligation lifting off of his shoulders.
"Enjoy it," Dean said, turning around to leave. He took a step away from the vampire only to halt when he felt a hand on his shoulder.
"Wait where um," Dean turned back around to look at Cas, just in time to see him pull back his hand quickly. And was it just his imagination, or did he see a hint of pink blush stain Cas' cheeks? "Where are you going?" Cas continued.
Dean cleared his throat and said, "Back to my motel room. Why?" He furrowed his brow and stared at the peculiar vampire, who currently refused to make eye contact.
"I was just wondering," Cas timidly said as he stared at the ground. He couldn't exactly understand why he was so shy all of a sudden. "I was wondering if it was possible for me to accompany you, so that I may enjoy your kind gift in peace, far from my family." He didn't bother to go into detail about how severe the consequences would be if they were to be discovered casually sharing blood.
There was a moment of silence as Dean contemplated his choices. He could either deny the vampire entry, thus not fully relieving his obligation, or he could put his trust into the creature and risk his own safety. Cas lifted his head up to look at Dean in anticipation of an answer, and Dean chewed his lip slightly as he thought. As he looked into Cas' pleading eyes, he noticed something. No where in the deep blue orbs was there any trace of the hatred that was evident yesterday. The more he stared into his eyes, the more compassionate and willing to help he felt.
Finally he had come to a decision. "Alright, alright," Dean said, bringing his fingers up to pinch the bridge of his nose. "Sure. You can come over for a little blood tea party or whatever." Dean knew that Sam would be all over his case about how idiotic it would be to invite the enemy into your base, but he couldn't worry about that now. His keen senses were on hyper-drive now, patiently waiting for Cas to give him even half a reason for him not to trust him.
Cas smirked at Dean's sarcasm, but he was relieved nevertheless. He was so relieved, in fact, that he couldn't help that his small smile grew into a real one. The big toothy grin that spread across his face was close to radiant, and Dean couldn't help but blush and smile himself, and then scold himself internally for being so girly.
"Welp," Dean said as he clapped his hands together, "We better get a move on while the sun's still up. You know what they say."
Cas tilted his head, causing Dean to involuntarily giggle. "And what might that be?" he asked.
Dean took a step forward, towards Cas' ear. As a reflex, Cas sucked in a gulp of breath. He was use to being the on who got close to people an intimidated them, not the other way around.
"The freaks come out at night," Dean whispered in his ear. He turned around and started towards the direction of his motel as Cas released the breath he was holding. As he followed Dean, he smiled a small smile to himself as he felt a jolt of pride rise up inside of him as he realized he was indeed, one of those freaks.