Sammy had the perfect mouth.
Soft, plush, warm; it turned the perfect shade of popsicle-stained pink after he kissed Dean or sucked him off. It felt just as good underneath Dean’s thumb as it did pulled taut around his shaft.
Sometimes he used that mouth to bitch and whine, and that turned Dean off at the best of times, but it was just as easy to turn him back on when Sam bit his bottom lip, dragged his tongue across it, or pouted at one of Dean’s jokes.
Sometimes it was as simple as Sam asking if he was asleep.