Dean smiled a bit at the sudden teddy bear he had, wrapping one arm up around Sam's shoulders and reaching for the shampoo while Sam rested on him like that. It was adorable, and sometimes he was reminded of the age gap, even if it was only four years. "I can go pick something up, Kansas isn't that big, there's gotta be somewhere close by." He was just glad they were in Lebanon and not Lawrence.
"Stay still, close your eyes," he warned as he put shampoo in his hand, dropping the bottle aside and rubbing his hands through Sam's hair to wash it for him. Fingertips scrubbing at his scalp Dean just enjoyed having Sam draped over him. He wasn't a hugger, didn't enjoy being mushy, but Sam was his weak spot and Sam made him much more affectionate, especially these days.
He'd get them both cleaned up and head out to get food for them. If Sam wanted pizza, then there was clearly a case of the munchies going on.