He's melting. Surely he's melting. That's the only explanation for the way his skin is crawling off him in order to escape the heat. He's melting. What a ridiculous way to go.
Seemingly he voices the thought out loud, because he could swear he hears John chuckling.
"You're not melting, you fool, it's just the heat."
Something is pressed to his lips, lukewarm and slightly salty. He sips at it without opening his eyes and it cools him as it runs down his throat. Blood. High grade stuff too. "That's it. Drink up."
He cracks his eyes open. The room is dark, white surfaces glistening grey in the low light. And it is John looming over him, concerned and half-smiling.
His throat is groggy, as if he were suffering with a cold, but one of the benefits of vampirism is that such things aren't possible anymore. "Wha-"
John has a hand under his neck, fingers gentle and why is he lying crammed into the bath? "You haven't been drinking enough. The heat got to you and you crawled in here before passing out. So no, you're not actually melting."
Sherlock groans, his head aching, as if it were two streets too wide. That would be the lack of blood. When did he get to be such an idiot that he thought he could melt? "I can't believe I actually said that."
"Oh that wasn't all you said. Apparently, I'm a delicious honey bee, and Mrs Hudson works on dangerous voodoo. I wouldn't say that to her. She could skewer you with a herb chopping knife."
Sherlock tugs his head down and presses their lips together, sliding his tongue in between John's briefly parted lips. "Oh do shut up, honey bee."