Dean lifted off enough to lick his lips to wet them and went back down on Sam, enjoying the noises his brother was making. He could very easily let himself get turned on by all this but he was trying hard not to, because he wanted this to just be about Sam. His brother gave up a woman he said he loved, for him, and that was something Dean understood very well. He'd tried to stay with Lisa and that had crashed and burned the second Sam came back, even despite him clinging onto it all still.
"Fuck, Sammy, you're so big," he huffed out, catching his breath for a moment, his face flushed from the unsteady breathing, and the heat of Sam's skin. Stroking his hand along Sam's dick a few more times, Dean swallowed down as much as he could, pushing his gag reflex a bit, and closing his eyes as he did it.