A meal eaten in a Mayfair Wankpit. There are usually at least five courses, none of which satisfy, and all of which cost far too much. The expression is derived from one of the traditional euphemisms for masturbation: five knuckle shuffle. The obvious implication is that the five course meal really is a pile of 'wank'.
Gwendoline, this five course knuckle shuffle is taking the edge off my apetite for the supper we will have in that other Mayfair Wankpit. I may well have to leave it on the table.