"Fuck," he breathed as Sam bit him that hard, and while he knew Sam was an ex-blood-junkie, he was just relieved the blood on Sam's lips was his; human, healthy, safe for him. It wouldn't turn him into something horrifying, like he'd seen him as years ago. He didn't even want to imagine that Sam coming back. Instead, he just focused on the pounding in his ears from the blood rushing through his body and the way Sam pushed hard against him as he came, the feeling of being flooded.
"Easy, Sammy." His voice was raspy, his hand settling on Sam's jaw as they both just came down from the high. "Feel good?" He was damn sure he knew how to get Sam to release tension now, and the fact that his brother would overwork himself on the files was obvious enough. He'd just have to focus on making sure Sam was having enough fun.
Pulling himself away from Sam on shaking legs, Dean reached to turn the water back on, leaning his forehead against the wall, Sam's come running down his thighs.