Oyster

From Frikipedia

Powerful aphrodesiac. Allegedly. No-one has ever been able to afford and stomach enough oysters to find out.

The only good thing about ordering oysters as a starter on a date is to discover early whether your partner of choice is ameanable to the idea of swallowing grotesque tasting gloopy substances.

You know, incase you decide to order a Bailey's.

Also a more convenient method of travelling on London transport than paying in cash.