Dean was fast losing feeling in his feet and he was pretty sure he was going to pass out if they weren't careful, but he honestly didn't care. He was certain now that Sam was right -- he was that rat that just hit the pleasure button until he died. He wanted to die this happy, when he eventually died, but he doubted that was going to happen.
"Fuck!" The hand on him made it infinitely harder to concentrate and Dean just held onto Sam's back, trying to move and having literally no rhythm to his movements anymore. He was just rutting against him hard, his face buried against Sam's neck and shoulder. He hated feeling this vulnerable, but it was so intense he didn't have a chance of keeping himself together.
Unable to even answer Sam, Dean let out several needy, whiny noises against Sam's neck, and then a final rough yelp before he came, his fingers digging into his brother's skin.