Blood and sex, pain and pleasure, all concepts that blurred into each other for a demon, so Crowley didn't question why he enjoyed it so damn much, both the biting and the being bitten, that rush of blood. And why he almost whined when Kol did pull away.
"I know, I know, I'm a terrible influence." He would have been grinning smugly if it wasn't for the kiss, and getting the kick of tasting his own blood on Kol's mouth. Where Kol's blood was sweeter and spicier, Crowley's own tasted smokier, possibly with slight hints of the whiskey he drank so much of.
"Natural charisma?" This time he did smirk before he half shrugged, awkward as it was still leaning over Kol. "Demon blood is just special, got that power behind it. Then again, so does yours." So did Kol in general. That pull that kept Crowley where he was.