To be fair, you are not supposed to, strictly speaking. The work the young master undertook was such that it was better that another party not realize they are in the company of a skilled professional in such matters.

[ This is all true, but it's also just as much Sebastian's aesthetic preferences, so. A grain of salt taken there would be fair. He looks amused by her doubt, though. ]

But if breaking and entering did not suffice, what sort of demonstration did you have in mind?