It's very hard for Dean to stop the snort that rises up when Castiel almost misses the hand-off. But that would ruin the... surprise, so Dean keeps as much of a straight face as possible and heads off to go get a refill.

When he comes back, the cups he's got are filled almost to the top, the same combination of Seven Up and Everclear. He hands them off, making sure they don't drop the cups, and then sips his own beer contentedly, pleased with how his and Brigitta's plans are going.