Sorry for asking what might be considered a dumb question, but how does one tip the sommelier?
Since the restaurants that I go to give me a credit card bill with one tip line, are you talking about slipping the sommelier something on the side (Say that last part 5 times fast)?
Most restaurants work on pooled tips these days. Does the sommelier partake in the pooled tips? Since you are tipping a percentage of the entire dinner (including wine), doesn't that take care of the sommelier?