Huh. Perhaps he's not quite as bad at this comfort-giving business as he thought. When Spike doesn't pull away, he makes the kiss warmer and deeper, not demanding but wide and deep and generous, giving of himself as he always does.
And then when he eventually has to break for air (becuase one of them still has to breathe) and Spike's head ends up on his shoulder, his hand curls around Spike's neck to show him it's okay to stay there, and he drops a soft kiss onto stiff, bleached hair to show Spike he's not alone.
And laughs softly at the words that come out. "Yes, you are. Let's get you home, eh? So you can sleep it off in comfort."