Dean was torn between proudly hugging Cas, and smacking the angel upside the head (actually, in hindsight, that was probably a bad idea...). Sure he was used to his boyfriend's straight faced, deadpan sense of humor, but seeing it used on some poor, unsuspecting woman was both highly amusing and excruciatingly embarrassing. Even if Cas had been telling the truth.
"Can I just say that you two make the cutest couple! How did you meet?"
"I recall sparks flying, and Dean stabbing me in the heart."
"You mean like a cupid's arrow? How romantic!"
"Oh no. With a six inch knife."
There'd been a long beat of silence, before the hunter finally snorted a laugh and pecked his angel affectionately on the corner of his mouth.
"Don't ever change." He'd murmured softly, and Cas had nodded with the ghost of a grin.
Neither noticed the woman smiling as they walked away.