"Woah--!" Dean didn't expect that either, and he shifted his knees to settle more comfortably, but he felt far too full up and every muscle in his body was straining with the feeling of it all. God, it was amazing. Sam's body was huge, and Dean didn't ever feel small next to him but he really did feel small like this. Not like a girl, never like a girl, but Sam's sheer force and power definitely made him feel smothered in the best of ways.
Both hands buried in Sam's hair, Dean kissed him harder, moaning into his mouth, his hips rocking down against his brother. Fuck, this was too good, and he was damn sure he should have been ashamed of himself for it, but that could come later. Right now every nerve ending was on fire and he didn't think anything could feel this intense.
With every motion, his cock rubbed against Sam's stomach and Dean broke the kiss to try to breathe, a series of ragged moans coming as Sam's dick brushed against that spot inside him.