[Ciel waves away the concern of whether the person would ultimately be untied or not, leaving that to a case by case basis. It's not like he's in the habit of keeping someone under his control indefinitely. He'd rather not waste the resources.
Plus, captives tend to get attached and that was just bloody annoying.]
Not very practical in a pinch then, or when I'm alone. [Tilts head in thought before diving right back in, this time with a bit more motivation.] Still. Wouldn't hurt to be familiar with it, just in case it's needed. Show me again, Sebastian.
[And this time, the look of concentration is intense, about on the same level as when he sees Sebastian wheeling out a double decker chocolate cake.]