I’ll go with 5 then, because reasons :)
Cas took the receipt from the barista, thanking her politely and dropping a dollar in the tip jar the way that Sam taught him. She smiled at him, with her head tilted so that she was looking up at him through her mascara-laden eyelashes. Idly Cas wondered if so much weight on them made it more difficult for her to blink properly.
He frowned when he got back to the table where Dean was sitting. The receipt seemed to be for the correct order- a grande caramel latte with extra foam that he was not supposed to tell Sam about, and a regular dark roast coffee- but the barista had written a different name on it.
"I think she gave me the wrong receipt," he murmured. "This says ‘Tiffany’ on it, not ‘Castiel’ like I told her."
Dean frowned and pulled the receipt out of his hands without warning. Cas thought about protesting, but then just shrugged mentally and watched Dean’s face instead.
Dean snorted and handed the receipt back to him. ”Dude,” he said, smiling the way he did whenever Cas missed something about human cultural norms. ”That’s her name. And that, right underneath it, that’s her number.”
"Oh," Cas said, looking at the number that he’d ignored, thinking it was maybe the contact number for this branch of Starbucks. What Dean said clicked in his head, and he nodded in sudden understanding. "Oh, this is part of a-a dating ritual, isn’t it?" he said. "She finds me attractive and wants to have some kind of romantic or sexual relationship with me."
"Yeah well, you’re hot stuff," Dean said, then his eyes widened. Something about what he said caused him to flush slightly. "Chicks dig the whole Constantine look," he added, gesturing at Cas’ outfit.
Cas looked down at his clothing. ”Do they?” he said. He’d only chosen this collection of clothing because it felt familiar, even if it wasn’t the outfit he’d worn for years after first taking a vessel. Dean’s eyes had lit up just a little bit when he saw it, anyway, so that was all that mattered.
"I have a grande coffee, and a grande caramel latte for Casteel?"
Cas stood to fetch the drinks. The barista- Tiffany, the receipt and her nametag said- smiled at him again, and this time he endeavored to smile back. She was pretty, he supposed, and what he could see of her soul with his fading grace looked bright and clean.
He handed Dean his drink and sat down again to sip his own. ”Perhaps I should ask her on a date,” he mused out loud.
Dean choked on the large gulp of sugary coffee he’d just taken. Cas leaned forward in concern, which Dean waved away as he coughed and sputtered. ”You’re-” he started hoarsely, then stopped to cough some more. ”You’re gonna go out with her?”
Cas shrugged. ”While I was human I found that there’s… comfort in having someone, even for a moment,” he said. And horrible, aching loneliness at wanting someone but not having them, but he didn’t mention that. ”I may not be human anymore, but there’s a lot that has… stayed with me.” He glanced at the register, where Tiffany was brightly helping another customer. ”Besides,” he added, “she’s quite beautiful.”
When he turned back to Dean, his friend was gaping at him, his face still blotchily red from his coughing fit, and his eyes practically bugging out of his head. Cas frowned. ”Are you alright?” he asked.
Dean cleared his throat, his expression suddenly masked by a teasing grin. ”Yeah- yeah, I’m fine,” he said lightly. ”Not as fine as you, obviously, you- uh, you player…” He coughed again and gestured vaguely toward the counter. ”Plus she’s- she’s hot, man, you should totally-” He swallowed. ”Totally hit that,” he finished, his voice trailing off.
Cas tilted his head and squinted at him, wondering about this sudden change. Humanity in general he sometimes had trouble reading; Dean was another story. But this reaction… something was off here. ”Dean, what’s-” He glanced down at the receipt in his hand, something occurring to him. ”Wait, are you- are you jealous?”
Dean opened his mouth, but no sound came out. His eyes were wide and his face suddenly pale, and he didn’t seem to be breathing. ”I…” he finally managed, but that was all he said.
"Dean," Cas said. Dean looked positively terrified at the sound of his own name. "If you’d like to go out with her, you can," Cas continued, passing him the receipt with Tiffany’s number on it. "I don’t have any strong feelings about her either way."
All the breath that Dean had been holding wooshed out. He stared at Cas, then slowly looked down at the receipt in his hand like he wasn’t sure how it got there. ”Right,” he murmured.
Cas took a sip of his coffee, and wondered what Dean’s caramel latte tasted like.