When you smuggle in your own alcohol to a restaurant in order to get your date drunk without having to pay a lot. Tell her to order just a soda then add in the alcholol you smuggled in. Saves lots of money and the drinks kick in very quickly.
Waiter brings you a soda. Once the area is clear of all staff you pour in a generous amount of alcohol, proceed to get wasted off just one "coke" for $2 and are now you and your date are considered cheap bitches. Leave stumbling and see what happens next.
(make sure you hide your drink or put it on the opposite side of the table as the waiter. This will ensure that they dont take it and give you a "fresh" refill")