"Sammy, pleeeaase sleep," Dean practically whines, he's begging here. He's been up for thirty-six hours himself, and he knows Sammy needs his nap otherwise he'll be cranky later. And if he's cranky later and Dad is back, he'll be pissed at Dean for not giving Sammy his nap. All Dean wants is to sleep. But he's supposed to be on guard and Sammy just keeps looking at him with those big sparkly eyes, and giggling, that is when he's not toddling round the room, bumping into things.
"Sammy, be careful," and Dean's not even fully aware of how he can make his body move so fast when he feels like his head is stuck in a vice, the screws drilling into his eyes, but he manages to grab hold of Sammy before he falls over, grumbling in defeat as Sammy just giggles again, "Sammy please," and he doesn't really know what he's asking, plonking Sam down onto the bed for what had to be the millionth time.
Dean sinks down to the floor, his back against the foot of the bed, eyelids fluttering until they flutter no more, refusing to open back up, and he mumbles "Just for a min-" slumping over onto his side. Out cold.
Sammy crawls to the edge of the bed to look down at his big brother, sliding off the side he manages to waddle round, falling down squarely on his butt, in front of the slumbering Dean. Reaching out he closes his fingers round Dean's nose, but he doesn't stir, so Sammy crawls closer, squeezing in under Dean's arm and settles against his chest with a yawn. Dean subconsciously tugging Sammy in closer and the youngest Winchester drifts off easily in his big brother's arms.