[He expected more protests - was prepared to ask if Ciel is really so eager to jeopardise his health and throw his life away now that they're so close to attaining their goal? That isn't allowed. Once Sebastian has decided on something, he won't have it stolen from him, not even something as frail as a human life.
But look at that: Ciel agrees. A little too readily, Sebastian thinks at first, but then he gets to the part about the drinks, and well. That's this opportunistic kid for you. He nods.]
You will want to to focus on those who drink heavily and yet seem but mildly inebriated. [Getting well and truly drunk is hard when you're inhuman.]